Yard & Garden: June 19, 2020

This is the Q&A for the Yard and Garden show for June 19, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: John Porter, Extension Educator, Douglas & Sarpy Counties

1. The first question of the show was from a walk-in listener. He had a dwarf Aberta spruce tree that was shooting out long stems of larger growth that didn’t look like the original plant. What is wrong with it?

A. This is reversion. Dwarf Alberta spruce commonly reverts back to the blue spruce parents. The dwarf Alberta spruce actually came from cuttings and grafted trees from a mutation in the original spruce tree. It is unusual growth in the main plant that the plant breeders have taken to make a new tree that is new and interesting. However, even after years of maintaining those traits, another genetic mutation can occur sending it back to the original parent growth of larger and faster growing. Those reverting parts, or large, wild growing branches should be pruned back or eventually the tree will look mostly like the general blue spruce or white spruce.

2. A caller has red raspberries that have been established for 7-8 years. Now the patch has a lot of grass growing in among the raspberries. How can the grass be controlled?

A. Mulch will be the best option for this area. Red raspberries grow upright so they don’t shade out the weeds as much as black raspberries. Glyphosate or Roundup can be used carefully around the plants as well. Use some type of a barrier between the grass and raspberries if sprayed or use a sponging type of applicator or paint it on the grass.

She also wondered what to do with the old canes of the raspberry plants. Should they be cut out?

A. Yes, remove them. Raspberries have perennial roots but the canes are biennial. The first year of growth for a cane is to grow the leaves, the second year is when that cane produces berries, then after that the cane dies out. Canes should be removed during the dormant season after they have fruited.

She also has peony plants and would like to know when is best to prune those back?

A. Peonies should be left to grow throughout the year and cut back in the fall after they turn brown. They need the leaves to grow throughout the summer months to build sugars for the roots so they can bloom well next year. The flower stalks can be removed, but the leaves should be left to grow until fall.

3. A caller has blackberries growing in a garden space in the middle of his native grass prairie area. There are now canes coming up and spreading throughout the prairie. How can those be controlled?

A. Blackberries will send out runners from the main plant. These runners are still connected by underground roots, rhizomes, so spraying a chemical on them could kill the main plant as well. It is best to just dig out the plants in the grass. You could use glyphosate or Roundup on the runners, but you would need to cut the runner first to cut the tie to the main plant.

4. This caller has spruce trees that have the tips of the branches dying and those tips are hooked over like a shepherd’s crook. They also have one that the top has died. What is wrong with these trees?

A. The tips of the branches look like the damage from a disease called sirococcus. To control Sirococcus shoot blight, apply a fungicide such as chlorothalonil (Daconil, Bravo) when new shoots are ½ to two inches long, typically in May; and repeat every 3 to 4 weeks if frequent rains occur. For more information, visit this Nebraska Forest Service publication on Diseases of Evergreen Trees. You would be a little late to spray now for this year, but could treat it next spring.

As for the top dieback, that is likely canker, a common disease in spruces. You will have to cut 6-8 inches below the dead area to get rid of that. This will remove the apical dominance in your tree and cause it to grow wider rather than upright. You can train a new leader by keeping one shoot growing more upright and taller than the others.

5. Is there a certain pH that is recommended for vegetable gardens?

A. The general recommendation is to have a pH close to neutral which is 7.0 The best growth from a vegetable garden is when the pH is 5.8-6.5 Below 5.5 or above 7.5 generally requires soil modification. To get the pH you can get a soil sample kit from your local Extension Office and send it in with a sample from your garden. For more information on how to do a soil sample, visit this NebGuide For more information on fertility requirements for your garden, visit this NebGuide

She also wondered about cedar apple rust and what to use to treat the cedar trees from this?

A. It is not necessary to treat cedar trees for cedar-apple rust because the galls on the trees do not harm the tree. If you have susceptible apple trees nearby, those should be sprayed when the orange galls are seen on the trees.

6. When is the best time to transplant roses?

A. Late fall is the best time to move roses, after they have gone dormant. They can be difficult to move, so be sure to take as much of the rootball as you can get.

How can you kill scrub trees growing around the roses?

A. Cut the trees off and paint the stump with glyphosate, or Roundup. You could also use the ‘Glove of Death’ method. This is when you wear a chemical-resistant glove and then put a cloth glove over that. Then, dip a few fingers of the gloved hand into Glyphosate and rub those fingers along the stem and leaves of the trees to kill them.

7. How can you manage grass in the vegetable garden?

A. Mulch would be the best option. No pesticides are labeled for use in the home garden without a Restricted Use pesticide license.

8. This caller has pampas grass that has grown large and now has a dead center. What can he do to get rid of the dead center?

A. The best option would be to dig up he pampas grass and divide it and then replant the new sections. This will eliminate the dead center. The fall would be the best time to do this.

9. A caller has a maple tree that was planted 3 years ago. Last year and again this year it has leafed out but the top third of the tree will lose all the leaves early in the summer and never regrow those leaves. What is wrong with it?

A. Unfortunately, it is likely that this tree is dying and will not recover. This is most likely caused by a root issue. A large root may have been injured when it was transplanted to this location or it could have a root rot issue. After discussions, she was watering the tree all night once a week. This is too much water for the tree. A newly planted tree would have a small rootball and would only need to be watered for about 20-30 minutes once a week, even a full grown tree would only need to be watered for about an hour at the slow trickle method. This tree was likely sitting in water for a few days after this long watering which would have caused the roots to rot and this will cause dieback from the top of the tree first followed by full tree death. It would be best to remove this tree and start over.

10. This caller has a pin oak tree with branches that hang over the sidewalk. When can she prune it and where should she prune the branches?

A. Oaks are prevalent to a disease caused oak wilt that is caused by a beetle spreading the disease when it feeds on a tree. The beetles are attracted to wounded trees, pruning the tree causes a wound. Because of this, oaks should not be pruned in the summer months. They are best pruned in the later fall. Prune back to the trunk, just outside of the branch collar. If you don’t want to cut all the way back, you can cut back to a side branch that is at least 1/2 the size of the branch that is being removed. Do not just cut to a random location in the middle of the branch.

11. A caller has thistles in her pasture. She went out to cut them the other day and noticed something had been feeding on the thistles. What was that?

A. There are some insects used to manage thistles, the thistle tortoise beetle is one. It is likely that this was feeding on the thistles which will help to control the population of the thistles.

12. This caller has 12 tomatoes, 2 of them have curling leaves at the top of the plant. What is causing this?

A. Unfortunately, we aren’t completely sure what is causing this damage, but it is widespread throughout the whole state this year. It could be from herbicide damage due to chemicals still being used later in the year with the cooler spring and sudden change of temperatures to very hot. There is also thought that it could be from the beet curly top virus. This could also be from watering issues such as over watering or underwatering. It would be best to just pull the plants out because if it is the virus it can spread to the other plants and if it is herbicide injury the produce would not be safe to consume. If the other plants look ok, this would be the best option. This condition is one that is being constantly discussed in Nebraska Extension this year.

13. The final caller of the show has an American Elm tree that 1/2 of it has leafed out and the other half has died. What is wrong with it?

A. It is likely that this plant has Dutch Elm Disease, just like the elm we discussed on the show last week. There is no control or prevention for this disease. American elms were mostly wiped out in the 1960’s due to this disease but a few have survived or came up naturally. The American elms that are still alive will eventually die due to the disease, it will get to them. He can send a sample into the UNL Plant Pest Diagnostic lab for confirmation, but if it is Dutch Elm disease, the tree should be removed.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

Yard & Garden: June 5, 2020

This is the Q&A for the Yard and Garden show for June 5, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: No guest host due to COVID-19 and social distancing

1. The first caller of the show would like to know when the proper time is to spray for bagworms?

A. After they have hatched, which is different every year, based on temperatures. It is typically around the middle of June. This week, the UNL Entomology department reported that bagworms have hatched in the Lincoln and Omaha area so if they haven’t hatched in Southeast Nebraska yet, they likely will in a week or so. We should be in the spray window for the next few weeks.

2. A caller has large trees in her yard that are shedding large amounts of leaves recently. What is causing this? Will the tree be ok?

A. This could be from a variety of factors. In some cases, the trees may have put on a large flush of leaves this spring. With the extreme heat and humidity recently, they dropped the extra leaves. They could also be leaves that have a minor leaf spot disease that has caused a large amount to drop off. Either way, the trees are still in good health with a full canopy of leaves and should be fine for future growth.

3. When can a large hosta be divided?

A. At this point for the year, it would be best to wait until next spring. It is now hot and windy so it would be very hard for the plant to tolerate being divided and replanted. Hostas are best divided in the spring before hot weather but after they have emerged well.

4. This caller has potato plants growing and now the edges of the leaves are curling up and turning brown. What is wrong with them?

A. The caller is watering his potatoes correctly, but does not use mulch. This could be one of two fungal diseases brown leaf spot or early leaf blight. Fungicides such as mancozeb or chlorothalonil can be used to control this, but the wet weather recently is likely the reason it is showing up. Mulching the plants will also help so that the spores don’t splash from the soil back up to the leaves of the plant. Be sure to clean up the garden at the end of the year and rotate the potatoes around to different areas of the garden each year.

2019-06-07 10.05.02
Herbicide injury on Tomato

5. A caller has tomatoes that the top leaves are tight and deformed. What is causing this and do they need to be replanted?

A. This is likely from herbicide drift, it is hard to say for sure without seeing the plants, but it sounds most like herbicide drift. This has started to become a problem again this year due to the change in weather. As we warm up, we see more problems with 2,4-D and dicamba products that turn to a gas and move to non-target plants. Tomatoes are very sensitive to drift from 2,4-D or Dicamba products. They should grow out of the damage, however because we don’t know exactly what product hit these tomatoes there is no way to know for sure when the product will be out of the tomatoes. I can’t say when or if these tomato plants will be safe for consumption this year.

6. This caller grew cucumber plants last year and the vines took over her small garden. Can she cut them back to keep them away from her other plants?

A. Yes, the vines can be cut to reduce the growth slightly. I wouldn’t cut too much off because that can reduce the yields. It might be better for her to use a bush cucumber in future years that will not spread as far. She can also try using a trellis to have the cucumbers grow up rather than out.

7. A caller has sapling trees growing up in her chain link fence. What can she do to kill them?

A. These should be cut off and treated with a stump treatment, painting a herbicide on the freshly cut stump. Roundup would be the best to use in this heat and around other plants. She asked about using a brush killer and this can be used, but shouldn’t be used too close to desired plants. Always read and follow the label when using pesticides

8. This caller was curious if bagworms would run their natural course and if he would be able to quit spraying his trees eventually?

A. Unfortunately, bagworms are here to stay. They will never fully go away. Bagworms, like all insects, go through peaks and valleys in their population and right now we are nearing the peak. This means we have very high populations that are doing damage to our plants. When the bagworm population drops, you may be able to discontinue spraying for a few years if the population isn’t large in your trees. For now, you will want to spray with the high populations.

9. What are the orange things on the cedars and what plants will they damage?

A. These are the galls of cedar-apple rust. This disease needs 2 hosts to complete its lifecycle. The galls are hard, gray/brown structures on the cedar trees over the winter. In the spring, when it rains, these galls open up to allow the spores to move to the apple trees. When the galls open up they are orange structures that resemble an octopus due to all the telial horns around the gall. The disease causes no problems to the cedar trees, but will cause lesions on the leaves and fruits of apple trees. If you have a susceptible apple tree, now is the time to spray with a fungicide to prevent the disease from affecting your tree. For more information, view this NebGuide.

10. Is there any reason to spray fruit trees this year since the blossoms all froze and no fruit will develop?

A. It wouldn’t be necessary, if you want to take a year off of spraying. The trees will still develop some damage on the leaves, but it shouldn’t kill the tree. For fruit trees in Nebraska, you can either spray throughout the entire summer to combat all the problems or you can not spray and have some problems. If there will be no fruit, it wouldn’t be necessary to spray the tree.

11. A caller has an old rose that bloomed but now the leaves look to be drying up. What is wrong with it?

A. It is hard to tell for sure without seeing the plant. There are a few different fungal diseases that could be affecting the roses now after all the rain we have seen recently. It may also be that the plants were shocked by the sudden onset of hot, humid, windy environmental conditions after the cool spring. They could also have damage from rose slugs, which are out right now. He also said they are surrounded by brome grass which could be causing competition issues. Most of these problems will fade on their own. If it is a fungal disease, there are rose specific fungicides that can be used. Rose slugs are minor problems and will go away as fast as they appeared, without chemicals.

12. The final question of the day was a caller who had planted a butterfly milkweed. overnight it was pulled out of the ground so he replanted it and it was again uprooted the next night. What is causing this? It is only on the new butterfly milkweed plant.

A. I assume this is damage from a squirrel or other type of wildlife. The best defense against wildlife damage would be to put a fence around the plants being damaged. There would be nothing else that would be very effective, or proven to work through research, in this case.

 

Yard & Garden: May 15, 2020

This is the Q&A for the Yard and Garden show for May 15, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: No guest host due to COVID-19 and social distancing

1. The first caller of the show wants to know how to plant the flowering plants he received from the Lower Big Blue NRD in Beatrice on the show last week? How far apart to space them and what type of growing environment should they be planted in?

A. Give the plants plenty of space, they are all large shrubs or small trees. The selection included Nanking cherry, redosier dogwood, lilac, crabapple, and caragana. They all need at least 8 feet of width and height. They all take full sun, but the redosier or red twig dogwood can take part shade. They could be planted on the interior of a windbreak to add to it or throughout a landscape.

2. A caller received a hydrangea plant as a gift for Mother’s Day. The flowers are now droopy. Should it be planted outside or what can be done to improve the flowers?

A. Yes, plant it outdoors. It can be planted in a container, but that would need to be protected over the winter months. Otherwise, plant it outdoors in part sun. The plant may also be finishing up the bloom period for this year, so remove those spent blossoms when they begin to turn brown.

3. This caller has iris borer. Should she dig up the plants now to remove the highly infected, mushy areas?

A. Leave them for now but clean out the mushy rhizomes as much as you can and spray the plants with an imidacloprid product to kill the larvae. Dig up the plants in the fall and clean them out. Next spring spray the plants earlier to prevent more damage. Also, be sure to clean off the dead leaves in the fall, this will destroy their overwintering location.

4. A caller has strawberries with a leaf spot disease. What can be done with them? He is already harvesting.

A. To prevent further spread and reduce diseases in the future, use soaker hoses to water rather than watering over the top of the plants. Also, make sure you have mulch around the plants which can also help reduce the spread of diseases. Captan can be used through the season for leaf spot disease. Spray every 10 days through the season, next year start before they begin to bloom. Be sure to follow the PHI listed on the product for strawberries. The PHI is the Pre-Harvest Interval, the amount of time to wait after applying a chemical before harvesting.

5. A caller has cedar-apple rust on his cedars that is harming them and causing the branches to turn orange. What can he do for it?

A. Cedar-apple rust is not damaging to cedar trees. If the branches are becoming covered in orange, it could be cedar-quince rust which can cause problems on cedar trees. You can spray the trees with Captan, Daconil, or Mancozeb to treat cedar-quince rust.

6. This caller has beans and popcorn that was planted from seed a while ago but it has not sprouted yet. Why is that?

A. It has been too cold for them yet. The soil temperatures are hovering just below 60 degrees and most of our warm season plants need at least 60 degree soil temperatures to grow well. Give them time, they should sprout in the next week or so as the weather warms up more.

7. A caller has Elephant Ear that was in the garage over the winter. She planted it in a lick tub before the last weekend with the cold temperatures. It has not yet sprouted, will it be ok or is it likely done?

A. It is still quite chilly for something like an elephant ear. Even though the plant had not yet emerged before the frost events last weekend, the lick tub may not have protected it enough since it is a bulb that needs to be dug up every year. Give it time, it might be ok though. It is hard to tell for sure yet.

8. This caller has wild violets in her yard. She had it treated twice in the fall and they are still coming up. What can be done about that?

A. Wild violets are very difficult to manage. They cannot be eliminated in a single treatment or even in multiple treatments in one year. It will take time and reapplications to really knock them back. 2 applications in the fall will be most effective. Apply a 2,4-D product in mid-September and again in mid-October for best control. Because we don’t know when the lawn was sprayed, or exactly what was spryed on it, it is hard to tell for sure why the plants are still so bad. Diligence with this plant would be best.

She also wanted to know how to control nutsedge in her lawn.

A. Nutsedge can be controlled with a sedge-specific chemical such as sedgehammer or sedge ender among others. Apply these chemicals before the longest day of the year, June 21st, to help reduce the population for next year. It isn’t a preemergence herbicide, but it will reduce the growth for future seasons.

Her final question was how to control weeds through the summer in an area that she has planned to overseed this fall?

A. Keep mowing the area will help reduce the flower and seed production through the year. She can continually spray roundup on the area throughout the summer to keep them down as well. Spray the Roundup 2 weeks ahead of overseeding to help kill it off before planting. She could use mesotrione, found in Tenacity, at seeding to help with weeds and not harm the seeding.

9. Why are the peonies not blooming yet?

A. With all of the cold weather we have had, it has slowed the growth of plants such as peonies. They are behind their normal blooming time for the year due to the snow and frost so late this spring. Give them time to flower a little later. They likely will not bloom by Memorial Day this year because of how cold it has been this spring. However, depending on the stage of development of the flowers when the snow and frost occurred, the blooms may have been damaged and may not open up this year. Give the plants time to recover into mid-June before giving up on the blossoms.

10. This caller is trying to grow rhubarb. It will start growing in the spring but then just stops growing larger and isn’t getting very large stalks. What is the problem?

A. It might be good to try a soil test to see how the soil nutrient levels and pH are where the plants are growing. You could try some fertilizer to help it grow larger. These plants were purchased from a flea market, from another grower, it might be that the plants were older and maybe not as productive. Try to start a new patch with new plants purchased from a nursery or garden center.

japanese beetle JAK582
Japanese Beetle, Image from Jim Kalisch, Retired from UNL Entomology

11. A caller has linden trees that had a problem with Japanese beetles last year. What can be done to control them this year?

A. After they have finished blooming, the trees can be sprayed with bifenthrin or chlorantraniliprole. Make sure you can get to the top of the tree for best control. He may need to call an arborist to spray the trees more thoroughly. Treating the yard for grubs can help. Don’t put a trap in your yard, this just brings more in from the surrounding locations.

12. This caller is wondering why her iris’ are not blooming? The plants of the same variety are blooming on one side of her house but not the other. Why is that?

A. The cooler weather is causing many of our plants to slow down or not bloom when they normally would be blooming. If the iris are blooming on one side of the house and not the other, and they are the same variety, this could be due to the microclimate on the sides of the house. One side may warm up sooner in the day causing those plants to warm up more and bloom sooner. Maybe the wind is hitting the one side more causing those plants to stay cooler longer. Give them time, they should all bloom eventually.

She also wondered why her celery is yellow. Is it due to the cold damage or is she overwatering?

A. It could be due to the cold weather. She is watering every other day for 2 hours per day with a sprinkler, this could be too much water. Monitor how much water is actually applied during that time by using a catch can. Vegetable gardens need about 1 inch of water per week. I would assume this celery is getting more than that.

13. Why are there so many seed stalks in the rhubarb plants this year?

A. The cold temperatures this spring are unusual and have “confused” the plants. This has pushed the plants to produce seed stalks. When rhubarb plants begin to produce seed stalks they push their energy into seed production and not into leaf and stalk production. To push that energy back into the stalk production we desire from rhubarb, cut the seed stalks off of the plant.

14. The final caller of the day has onions that are turning white and falling over. He didn’t cover them in the freezing weather last weekend. Is it cold weather injury that is causing this damage?

A. It is likely that this is from the cold temperatures. Even onions can be injured by temperatures in the low 30’s like what we saw. If there is green in the lower leaves, they might regrow.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

Yard & Garden: May 8, 2020

This is the Q&A for the Yard and Garden show for May 8, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: No guest host due to COVID-19 and social distancing

1. The first caller of the show has shrubs that bloomed this spring, when can they be pruned?

A. Any shrub that blooms in the spring should be pruned within about 3 weeks following the spring bloom period. This would include plants like lilac, forsythia, and the spring blooming spireas.

2. A caller heard me discussing the need to cover tender annuals for the next few nights with the cold temperatures predicted. Do those need to be uncovered during the day or can the cover just stay on for the next few days? Does she need to cover her wisteria or strawberries that are just beginning to bloom?

A. The plants that should be covered are annuals and tender perennials, this includes the warm season crops that have already been planted in your garden this year. You can cover them with a sheet, a row cover, or a bucket. They should only be covered at night. In the morning, when the temperatures warm up above 40 degrees, the coverings should be removed to allow the plants to receive sunlight. Perennials, including wisteria, should be fine. Strawberries that have blossoms set would push new flowers and fruit later but if you don’t want to lose this first crop, you may put a row cover or sheet over the plants to protect the developing fruits.

3. This caller has a flowering tree that is suckering in the lawn. How can they control the suckers without harming the tree?

A. If these are growing in the yard, they can just be mowed over and will eventually die but not harm the tree. You can also cut the suckers off individually, if desired. Don’t treat these with any herbicides like roundup because it can go into the main tree and kill that as well. While some products, such as Sucker Stop are available, these will only slow sucker growth; not stop it. Some trees and shrubs are more prone to suckering. For example, crabapples, purple leafed plums and lilac.

4. A caller has 3 acres of bare area to manage. What is the best or cheapest options for him regarding grass or some other type of covering?

A. Native grass or pollinator or wildlife mixes would be a great option for this type of location. You can purchase seed at many locations including Anderson Seed from Odell or Stock Seed Farms from Murdock.

5. This caller has black spots on her grass that have recently showed up. She wasn’t sure the type of grass but most likely it was Kentucky bluegrass.

A. It is hard to tell for sure what the problem is from the description given. I asked for a photo to be emailed to know for sure.

cedar-apple rust gall
Cedar-apple rust gall on Cedar Tree

6. A caller has cedars that have developed odd orange structures on the branches. What is that and how can it be controlled?

A. These are the galls of cedar-apple rust. This disease needs 2 hosts to complete its lifecycle. The galls are hard, gray/brown structures on the cedar trees over the winter. In the spring, when it rains, these galls open up to allow the spores to move to the apple trees. When the galls open up they are orange structures that resemble an octopus due to all the telial horns around the gall. The disease causes no problems to the cedar trees, but will cause lesions on the leaves and fruits of apple trees. If you have a susceptible apple tree, now is the time to spray with a fungicide to prevent the disease from affecting your tree. For more information, view this NebGuide.

7. This caller has asparagus growing. This is the 4th or 5th year of growth. He has fertilized often but not this spring. He did use a weed and feed on the asparagus, but asparagus wasn’t listed on the label. Why is his asparagus growing so spindly?

A. As we harvest, eventually the spears will start to get spindly which means that is the time to quit harvesting for the year. However, the weed and feed product may have some negative consequences on this plant. He didn’t know what exactly the product was that he used but he said it didn’t have asparagus listed on the label. In this case, the product should NOT be used on the asparagus. Make sure to always read and follow the label on pesticides and only use it on plants listed on the label.

8. A caller has planted potatoes a couple of different times this year, but they continue to not sprout. What would be the problem?

A. The weather has been fairly cool, and especially cold overnight. The plants are just waiting for more desirable weather before growing. Give them a little more time and they should grow as long as a disease doesn’t set in or they rot in the ground.

9. If volunteer redbuds have come up throughout a landscape, can they still be moved to a more desired location this year or is it too late?

A. Yes, they can still be moved now. As long as they are moved prior to the hot, dry environment of late June through July and August, they should be fine.

10. What is the best way to manage weeds around asparagus?

A. Mulch is the best option to keep weeds down around asparagus. You can use the preen that has asparagus listed on the label to control annual weeds. Otherwise hand-pulling will help keep them down as well. At the last harvest of the season cut down all the spears, so there’s no foliage or anything above the ground. Rake the soil over the top of the spears. Then spray the plants with glyphosate (RoundUp). Glyphosate becomes bound by the soil particles when it hits them, so will not damage the crowns below ground. This will control annuals and tough perennial weeds. The spears will then re-emerge from the soil and not be damaged by the glyphosate at all. Apply some mulch to help with the weed control, then Preen.

11. This caller gets little brown spots on the leaves of her cucumber plants every year. This often will kill her plants over time. Is there anything she can do to control this so her plants will survive longer?

A. Using mulch and watering at the base of the plants with soaker hoses will help. Overhead irrigation, such as with sprinklers, can splash disease spores from the soil to the leaves of our plants or from leaf to leaf or plant to plant. Watering from below helps reduce the spores splashing. Mulch also helps to keep the separation from the soil where the spores are. Fungicides, such as a copper fungicide, could also be used if desired. Make sure that cucumbers are listed on the product and follow the PHI (Pre-Harvest Interval) for length of days to wait from application to harvest.

12. A caller has spiny vines growing up the trees in her windbreak. How can she kill the vines and not harm the trees?

A. You can go through and cut off the vines and follow that up with a stump treatment using either 2,4-D or a glyphosate product, such as Roundup. Use the concentrate and just paint it on to the freshly cut stump for best control. Do NOT use Tordon, that will likely kill the spruce trees, and it is against label directions. When cutting the vines off at the base, they will stay in the tree but they will die because they have no roots. Treating the base of the plants will kill the roots to eliminate the problem with regrowth.

13. This caller has a patch of asparagus is not doing well this year. He recently piled logs nearby the patch. Would those logs be causing a problem with the growth of the asparagus? The logs are about 3 feet from the asparagus.

A. The logs shouldn’t be causing a problem from that distance, there isn’t black walnut in the wood piled there. It may just be that the asparagus needs to be fertilized. A general fertilizer can be applied in the spring to help with growth. If the spears are getting spindly now, harvesting should be discontinued. The plant will tell you when to quit harvesting based on the size of spears.

14. A caller has cucumbers, zucchini, and potatoes that have just emerged their first leaves. Should those be covered this weekend with the cold weather that is predicted? Would peonies need to be covered?

A. Yes, those warm season crops that have very tender new growth should be covered for the next few evenings. Remember to uncover them during the day. The peonies should be fine, but a freeze could damage the developing flower buds depending on how cold it gets, how long it stays that cold, and how far developed the buds are.

15. This caller asked how to spray her apple trees to prevent problems with insect and disease problems.

A. Orchard fruit tree sprays will combat both insect and disease problems on fruit trees. Sprays should begin as soon as pink is seen in the buds, but should cease during blooming. Since this caller hasn’t begun spraying yet, it would be fine to just start as the blossoms are falling off the tree. You want to allow the pollinators to come to the tree without harming them, so no sprays should be done while the trees are blooming. This spray should be applied every 10-14 days through the growing season, up until harvest.

16. The final caller of the show has a concolor fir that the needles on the bottom third of the tree have turned brown. What is causing this problem?

A. It was hard to determine the problem with this fir over the air. I asked for follow-up photos to help diagnose the problem.

 

Yard and Garden: June 28, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for June 28, 2019. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 2, 2019. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Dave Olson, Forest Health Specialist from the Nebraska Forest Service

1. The first question of the show was about a red twig dogwood that is overgrown. Can it be pruned now?

A. It would be better to wait until fall to prune it. It can be thinned by removing 1/3 of the canes at ground level. This type of pruning can be done every year to remove the oldest, least productive canes from the plant. You can also do a rejuvenation pruning on it by cutting the whole plant off 6-8 inches above ground level in the fall. This will help to bring back a deep red color in the stems that may have faded over the years. If you rejuvenate it this fall, it will not bloom next year, but should after that.

2. A caller has a couple of blue spruce trees with low hanging branches. Can those branches be removed now to make it easier to mow around?

A. Yes, you can remove those lower branches for mowing around. That can be done most anytime, but it is best in the late winter while the tree is still dormant.

3. This caller has green ash suckers that are growing up in her gooseberry bush. These have come from an ash tree that was removed a few years ago but is still suckering. What can be done to kill the ash seedlings and not harm the gooseberry bush?

A. It might help to get someone to grind out the ash stump to help fully kill the tree. If the stump is still there, the roots are likely still alive and doing what they can to bring the tree back, which includes suckering in other locations. Otherwise, you can just keep cutting the suckers off and eventually the roots will run out of energy. You could also cut back these suckers and paint the fresh cut with a roundup or glyphosate product.

4. A caller has gray bugs with long black antennae that are found in her garden. What are these and how can they be controlled?

A. These bugs could be blister beetles. They can sometimes come into our gardens. Certain years, they can be found in high population. If they are feeding on your garden plants, you can spray with some sevin or eight to control them.

She also wanted to know what would cause her iris leaves to turn yellow with brown spots in the yellow color?

A. This is likely from Iris Leaf Spot, a common fungal disease of Iris plants. This can be controlled fairly well by removing and destroying the infected plant material as it shows up. When watering, don’t water over the foliage which will spread the disease. If necessary, a fungicide such as Daconil can be used if sanitation isn’t enough.

5. This caller is trying to re-establish a new windbreak. For a quick windbreak solution, would the quick growing willow-type trees work well?

A. Willows and other very fast growing trees would not work as a windbreak, even temporarily. The fast growth in these trees would not be very strong growth and therefore it would break a lot in windy situations. It would be better to go with a larger shrub such as a viburnum or serviceberry to help fill in until the trees can grow up larger. These shrubs would block the winds quicker than some trees but withstand strong winds and storms much better than willows.

2015-07-30 16.59.34
Bindweed

6. What can be done to control bindweed in phlox?

A. Among other plants it is best to use the “glove of death” which is when you wear a chemical-resistant glove and then put a cloth glove over that. Then, dip a few fingers of the gloved hand into Glyphosate and rub those fingers along the stem and leaves of the bindweed to kill it. Basically, the idea is to keep it from flowering and producing more seed, hand pulling will help keep new seed from being deposited into the garden which can be viable for up to 60 years.

7. A caller wants to know if she can use the Extended control Preen on her petunias, they are not listed on the label?

A. If it is not listed on the label, you can’t use that pesticide on that plant. Stick with the general preen that has the petunias on the label to ensure correct application.

8. This caller has a pin oak tree with lower branches that are in the way of mowing. Can those be removed right now?

A. No, it is best to avoid pruning oak trees during the summer months. Oaks are susceptible to a disease called oak wilt that is spread by a beetle. The beetle is attracted to the trees after they have been pruned. Oak wilt can kill the tree if it is introduced to the tree. Wait until the fall or until the trees are dormant or early next spring before April to prune oak trees to avoid this disease.

9. A caller had her driveway lined with small mums that grew only to 1 foot tall. Over time some of them have been dying periodically throughout these lines. What could she switch to that is more winter hardy and stays at the 1 foot tall size?

A. That is a problem with some of our newer mum varieties, they just aren’t as winter hardy as they are advertised to be. The 1 foot tall size is difficult to find, I would suggest a groundcover to stay so small. Most other plants are going to be 2-3 feet tall at least. There would be some nice phlox that would look nice lining a driveway.

10. This caller has an oak tree that was pruned. The pruning is about 20 years old and has recently started oozing. What is wrong with it?

A. The tree could have borers or it could be a slime flux. It would be best to have a Certified Arborist look at the tree to determine what is causing the oozing and what can be done about it.

11. A caller has a mulberry tree with a flower bed underneath the tree. The high number of mulberries are now falling off the tree and rotting on the ground which is attracting flies. Is there anything that can be sprayed to treat for the flies but not harm the tree or the flowers growing underneath?

A. This is difficult since the fruit is already maturing and falling from the tree. If it was caught earlier, the fruits could have been quickly harvested by placing sheets underneath and shaking the branches. Once the fruits are on the sheets, they can be used or destroyed away from the tree if there are too many for consumption. Leaving the fruits to decay around the tree is attracting the flies. Using a sevin around the plants could help reduce the flies, but it won’t eliminate them entirely. Once the fruits have decayed completely, the flies should not be a problem.

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Rust on a Pear tree

12. This caller has an apple tree that gets rust even when they are spraying and then it moves onto their peach tree. What can be done for this disease?

A. Rust is found on apples, crabapples, and pears, but not on peaches. I would say there are 2 different problems. As for the rust, if the timing or chemical formulation is off a bit, the spraying will not work. Be sure to spray the trees with either copper fungicide or orchard fruit tree sprays. These sprays need to be applied every 10-14 days through the growing season starting at bud break, skipping the time frame while the trees are blooming to avoid harming pollinators. As for the peaches, it could be a fruit rot or other disease. The orchard fruit tree sprays will work on those as well, but it would be for a different disease on the peaches, not the rust.

13. A caller has a 6-7 year old apple tree that was girdled all the way around the tree this past winter by rabbits. It seems to still be growing fine, does the death just take a while after damage like this? Will it eventually die?

A. It could be ok, but most likely it won’t live through girdling all the way around the tree. If the damage was minor and the tree is able to seal up the wound, maybe it will be ok. I would say just to keep an eye on the tree and give it time to see if it gets better or worse. If the canopy isn’t full or has top dieback, you would want to remove it before it becomes a hazard.

14. This caller had large hail last week. It hit his vegetable garden. Is there anything he can do for the plants now? Will they survive and produce?

A. This depends on how badly the plants were injured and if the damage is mostly just on the leaves. It is a situation where time will tell, the damage may not be fully present for a while. There is nothing that can be done to fix this type of damage once it gets hailed on.

15. A caller has bare spots in the lawn due to shade under pine trees. What can be done about that?

A. Grass doesn’t grow in the shade. It would be best to use mulch under the trees or try to plant something else that thrives in shade conditions such as carex, sedge, or other groundcover or use shade perennial plants. Remember to plant the right plant in the right place for best growth.

16. This caller has rose with leaves that were eaten off of it. What would do that and how can it be managed?

A. This could be from rose slugs, but the damage sounds worse than what rose slugs do. It could be from Japanese Beetles. Those can be controlled with sevin, bifenthrin, or neem oil applied to the leaves. Be careful to avoid hitting the flowers with insecticide sprays to avoid injuring pollinators.

17. The last caller of the day wants to know how to renovate her strawberry plants?

A. According to John Porter, UNL Extension: She will want to manage weeds, but do nothing to disturb the plants. They should be left to grow until the end of the season. Tilling is okay around the beds, but in the beds hand pulling or minimal cultivation would be ideal to avoid damaging roots. Using a mulch like straw or woodchips can help control weeds in the bed. If the strawberries are a Junebearing variety, they are done producing for the year.  However, if they are a day neutral or everbearing variety they will have more production cycles throughout the season.

 

 

Yard and Garden: June 21, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for June 21, 2019. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 2, 2019. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Steve Karloff, District Forester for the Nebraska Forest Service

1. The first question of the show was about a Colorado Blue spruce tree that is turning brown throughout the whole tree. It seems to be starting at the ends of the branches. What is wrong with it?

A. This could be that it is simply too wet. The excess moisture this year is causing problems with a lot of our plants. Colorado Blue spruce trees grow best in the conditions in Colorado with a lot less humidity and moisture. Steve has seen quite a few spruces turning brown this year, most likely due to root rot issues from the high precipitation from this spring. Unfortunately, there is nothing that can be done to fix this problem.

2. Can you still prune forsythia shrubs this late into the year?

A. No, it would be better to wait. The general guidelines are to prune spring blooming shrubs within a couple of weeks after they have finished blooming for the year and to prune summer blooming shrubs in the late winter before they bud out for the year. At this point, pruning the forsythia will affect the blooms and it would be too hot to prune in the summer.

3. A caller has cherry trees that he planted in the spring. Now the leaves have wilted and died back. Why did this happen?

A. After discussion it was determined that the trees were purchased from a mail-order service and were delivered bare root. He planted them within a day of receiving them, which is advised because they will dry out quickly with no root ball to hold water. It was advised that he scratch the bark on some small twigs to see if it is green underneath the bark which means the tree is still alive. If under the bark is brown, the tree is dead. It could be an issue from the nursery or through the shipping process. It would be better to purchase trees locally.

He also wanted to know if he could remove the cedar trees on his property to eliminate the problems from cedar-apple rust?

A. No, the spores from cedar-apple rust will spread up to 2 miles. Removing the close cedar trees won’t stop the disease because it would be nearly impossible to find a location in Nebraska where you can get more than 2 miles away from a cedar tree. It is best to just spray susceptible apple trees or plant new trees that are resistant to the disease.

4. This caller has a weed called pineapple weed. Can you use a granular herbicide to control it?

A. Pineapple weed is an annual plant that is often found in poorly maintained areas, typically along driveways or along gravel areas. This weed can easily be controlled earlier in the season with a pre-emergent herbicide such as dimension or another that contains dithiopyr. For post-emergent control, glyphosate products such as Roundup could be used. The granular herbicide will likely not be very effective on pineapple weed.

5. A caller has strawberry plants that are producing very small berries and not a lot of those. It was hit by herbicide drift at one point, but seems to be recovering. Is the herbicide causing problems with fruit production or why are there so few berries that are so small?

A. The herbicide drift may impact the fruit development if it was hit while it was flowering that could have damaged the flowers before they were able to produce fruit. Otherwise, the small fruits are fairly common for the everbearing types of strawberries. Since they continue to produce through the season they will not produce the larger fruits that June bearing plants would have.

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Hollyhock rust, underside of leaf

6. A walk-in listener has a hollyhock plant with a lot of brown spots that are raised bumps on the underside of the leaf. What is causing that?

A. This is hollyhock rust. This is a common problem for hollyhocks, especially in this wet year. Remove the heavily infested leaves if you cannot remove all infested leaves and destroy those. You can use a copper fungicide on the plants to reduce the spread or re-infestation. At the end of the season, be sure to clean up all the leaves and plant material to reduce overwintering location to see less of the rust next year.

She also wanted to know what would cause a row of holes in her canna leaves?

A. This would be from Canna leaf rollers, a caterpillar. They can be controlled with a systemic insecticide applied to the cannas early in the season before the damage begins or by using Bt or Sevin once the damage begins.

7. This caller has an ash tree she would like to save from Emerald Ash Borer. What can be done now to ensure it lives?

A. Wait until Emerald Ash Borer is found within 15 miles of the tree prior to beginning treatments. Treatments are not necessary for an insect we haven’t found in the area. Even if defoliation has began on the tree when it is first identified in the area, treatments can be successful. Each time trunk injections are done they wound the tree leading to more problems.

8. How do you eliminate woodchucks from a garden?

A. They can be deterred with the use of a heavy-duty fence around the garden. The fence needs to be 3 feet tall and made of 2 inch mesh woven wire or heavy poultry wire. They can also be trapped using apples or carrots as bait. For more information on Woodchucks, view this guide.

9. Can you grow an avocado tree in Nebraska?

A. This would have to be an indoor tree. They will not withstand Nebraska winters outdoors.

10. A caller has wild roses that have some dead stems throughout the plant. Should those dead stems be removed?

A. Yes, you can cut out the dead canes of the shrub at any time.

He also wondered about tiger lilies. They were constantly mowed last year and haven’t come back this year yet. Will they come back?

A. If they haven’t regrown yet, it is likely that they have died. I would suggest replanting.

11. This caller has a big, green leafy plant that grows 4 feet tall and 6 feet wide with leaves similar to rhubarb plants. What would that be?

A. This sounds like Common Dock. It can be mowed off or sprayed with a roundup or glyphosate product now. In the fall, you can treat the plant with a 2,4-D product.

12. The last caller of the day has roses with holes in the leaves. What is causing that?

A. This is likely due to rose slugs. They are a common issue right now in roses. They will likely be finishing up their damage cycle soon and then they will pupate and become adult sawflies. The damage is minimal and they don’t need to be controlled with an insecticide which could harm pollinators coming to the rose flowers.

Yard and Garden: May 10, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for May 10, 2019. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 2, 2019. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Hosts: Kevin Christiansen, Horticulture Instructor at SCC Beatrice & Chelsea Tietjen, Agronomy and Entomology Instructor at SCC Beatrice

1. The first caller of the show wants to know when to start spraying his apple trees with the orchard fruit tree spray? He also wants to know if it is too hot here to grow cabbage because it is hard to get a harvest?

A. Orchard fruit tree sprays will combat both insect and disease problems on fruit trees. Sprays should begin as soon as pink is seen in the buds, but should cease during blooming. Since this caller hasn’t begun spraying yet, it would be fine to just start as the blossoms are falling off the tree. You want to allow the pollinators to come to the tree without harming them, so no sprays should be done while the trees are blooming. This spray should be applied every 10-14 days through the growing season, up until harvest.

As for the cabbage, it should be fine growing here, but some years it can get hot quickly and that can cause our cool season crops to bolt. Cabbage may be better grown in the fall due to the quick warm up in spring that usually happens here in Nebraska. For more information on growing cabbage, visit this article from Lancaster County Extension.

2. This caller was wondering if we would see bagworms later this year than most years due to the colder weather? He also wondered what is the best control for them and when to control them?

A. It is likely that we will see bagworms a little later this year due to the cooler spring we have had. They will hatch at different times in the year because their hatch is weather dependent. Starting in late May, check weekly for the small bags to begin to show up on the trees. When the small bags show up and until they are up to 1/2 inch in length you can spray. Tempo or Bt would be best for control.

3. A caller has lilacs that were planted 2 years ago. They were a small cutting at 1 inch tall when they were planted and now they are only 4-6 inches tall. What fertilizer can he use to get these to grow faster?

A. Mulch would be a better option for these plants since they are so small. This would protect them from weed competition and from accidentally being mowed over and would do much more for the plants than fertilizer would. It would also be a good idea to put a fence up around them to prevent rabbits from chewing them off since they are so small.

4. This caller has cedar-apple rust that is showing up on his cedars. He has sprayed his apple trees, but does he also need to remove the galls from the cedars?

A. The galls will not hurt the cedars and as long as you sprayed the apple trees, that should be sufficient. Pulling the galls off won’t stop the disease for future years because the spores can spread up to 2 miles so they will come from other cedar trees.

5. A caller has a rhubarb plant that is flowering and not producing the stalks for consumption. What can be done to improve stalk production?

A. Cut the flower stalks off at the bottom of the stalk. These flower stalks take energy from the plant. The energy is moved from the leaf production to flower production. The abnormal weather this spring has caused rhubarb to flower more this year than other years.

6. When do you prune snowball bush and lilacs?

A. After they complete blooming this spring, remove 1/3 of the stems at the base of the plant. Remove the largest, least productive canes and leave the smaller, younger, more productive canes.

This caller also wondered what do do for the purple flowering weeds and dandelions in the yard?

A. The purple flowering weeds are henbit. They are a winter annual and will soon die when the temperatures warm up, likely in the next week or so. There is no reason to spray them now. Dandelions are best controlled in the fall with an application of a 2,4-D product. Spray them in the middle of September and the middle of October. The later application in the fall will also help kill henbit as it emerges in the fall to reduce the population for next year.

7. A caller is building a raised bed in his landscape. Does he need to put rock at the bottom to help with drainage?

A. No, it wouldn’t be necessary to add rock to the bottom of a raised bed to help with drainage. Raised beds are built up on the sides with an open bottom. That will be drainage enough for them. Be sure to use good quality soil and some compost, don’t use soil from your yard.

Buckbrush, Steven K. UNL
Buckbrush Photo from Steven Knezevic, Extension Weed Management Specialist, from Cropwatch.unl.edu

8. How do you control buckbrush in the pasture?

A. According to the Guide to Weed Management from Nebraska Extension, 2,4-D will work on buckbrush in the pasture. For more information visit this cropwatch article.

9. This caller has lillies that are not growing well. The daylilies are short and blooming but they are not growing big at all. Other plants in the bed are fine and these daylilies in other locations are growing larger. What is causing the problem?

A. This may be a soil issue. It might be good to do a soil test. It could also be that the soil is compacted more in that location that are constricting the roots and limiting growth. Add some compost to the soil and work it in around the plants to try to reduce the compaction. A general fertilizer could be tried as well. It also could be that the plants are maybe planted a little too deep. It might be helpful to dig up the plants, add compost or manure to the soil, and replant the daylilies a little higher in the soil profile.

10. The last caller of the day had 2 questions. She is rejuvenating her landscape beds, should she use landscape fabric in them? Also, she has a trumpet vine growing on a trellis that has a lot of dead branching in it, what can she do to remove the dead growth and rejuvenate these vines?

A. Landscape fabric is not necessary in the beds. Landscape fabric can restrict the movement of moisture into the soil and harm the plants. Also, soil and weeds can move in on top of the fabric which defeats the purpose of using it. Finally, if you ever want to change that bed in the future, the landscape fabric is very difficult to remove.

As for the trumpet vine, it can be cut back heavily, but it would be best done early next spring rather than now because it is getting a little late this year. Remove the old, unproductive growth and leave the smaller, healthier growth.

Yard and Garden: May 19, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for May 19, 2017. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 28, 2017. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Jim Kalisch, Insect Diagnostician for Nebraska Extension

If you enjoy reading my Q&A from the show each week, take my quick survey at: http://go.unl.edu/44qr and be entered to win a free plant book or some free UNL gifts.

1. The first question of the day was from a gentleman wondering how to tell when to water his self-watering containers? There is no viewer or gauge to show the water level on the outside of the container.

A. Because a self-watering container is continually watering the plants in it, it can always be refilled. In this case, this container will keep your plants watered for at least a week to two so, they should be refilled before they completely dry up. I would suggest refilling the reservoir every week to 10 days.

Bagworm4
Bagworm

2. A caller has bagworms in their cedars. What is the best way to see them before they get too big to treat?

A. They haven’t hatched yet this year. Mark the branch you have a living bag on with flag tape to check the same bag every week from now until they hatch. You can also place a few bags in a container and keep it in the tree to see when they hatch in the container. Wait a couple of weeks after the initial emergence to ensure that all of the bagworms have hatched before spraying. The bags in the shade will take longer before they hatch. Once they have hatched, Bt is a good insecticide to use when they are young or you can use a product containing bifenthrin in it for longer lasting control.

3. This caller is wondering what types of problems we can expect in the garden, lawn, and trees this year due to the excess rain?

A. The rains in the spring tend to lead to more fungal diseases this time of the year, but they are not terribly harmful and many should fade out as the summer heats and dries up. Many things to watch out for would include fungal diseases in the lawns and trees. We are already seeing Peach Leaf Curl, different fungi in blue spruces, anthracnose on the leaves, and mushrooms popping up in our lawns. We will also see more problems from earthworms and fungus gnats which are mostly nuisance problems.

2015-09-22 18.45.39
Squash bugs on a zucchini

4. How do you effectively control squash bugs in the vegetable garden?

A. Squash bugs are difficult to control in our cucurbit vegetables including zucchini, squash, pumpkins, gourds, melons, and cucumbers. The best option is to kill the adults when they first emerge to manage the population before it explodes. Watch for the eggs as they develop on the underside of the leaves to destroy them before they emerge. Switch to other chemicals for management besides just using “Sevin” for control, which they are becoming resistant to. There are also lures that can be used for them which might help early in the season.

5. A caller has an Oregon Trail Maple that leafed out early this spring. Now the leaves are slightly cupped and turning yellow along the edges. What would be causing this?

A. This sounds like frost damage. If the leaves came out early, they may have been nipped by a light frost in late April. We are seeing this problem throughout many trees and shrubs this spring. The leaves may drop entirely from the tree, but the tree will then push secondary buds to produce new leaves that are not injured.

6. This caller wants to know how to propagate a lilac and a hydrangea.

A. For lilacs: A cutting can be taken from the shrub. Cut off a small, pencil-sized, branch and place it into rooting hormone than plant it into a pot of gravel that is kept moist. Once roots have formed, the plant can be transplanted into the ground. They can also be propagated through a process called layering which is where you bend a flexible branch down to the ground and plant it to allow roots to form on the branch while it is still attached to the main plant. Once roots form, cut it from the parent plant and transplant it. There is more information on this in the NebGuide: Lilacs

Hydrangeas can also be layered to produce new plants or they can be divided. It is too late to do the division this year, but early next spring you can dig up the plant and use a spade to divide the main plant and replant the pieces. Depending on the side you can get 2-4 pieces from a divided plant.

7. Is cedar-apple rust damaging to cedar trees?

A. Cedar-apple rust shows up in the spring on cedar trees as a orange, slimy, ball with horns. This is the gall that opens up with rains in the spring. Cedar-apple rust is not harmful to the cedar tree, it just uses the cedar trees as an alternate host through the winter. When these galls are seen on the cedar, that is the time to spray any susceptible apple, crabapple, pear, or hawthorne tree to avoid damage to them. For more information view this NebGuide

8. This caller has a pink peony that hasn’t bloomed well this year. There is some discoloration and fuzzy appearance to the leaves and buds. What would cause that?

A. This sounds like botrytis blight, a common fungal disease to our peonies. It is not very harmful to the plant itself, so it is not necessary to control it. In the fall, make sure you remove and destroy all of the plant material to reduce the spread to your plants next spring.

9. A caller has a Chanticleer Pear with leaves that have black spots on them and the top isn’t leafing out this spring. What would cause that?

A. This could be due to frost damage as well. Or check the tree for oozing sap along the trunk or branches. The damage could be from borers. It might also be from fireblight which would cause the leaves to turn black on some branches where the end of the branch hooks over like a shepherds crook. Fireblight is likely since this showed up in the tree last summer. If it is fireblight, prune out the infected branches and dip your pruners into a bleach water solution in between the cuts.

10. This caller has roses that had dieback from the winter. She pruned them off in early April and now it looks like the only live growth is coming from the ground. What is wrong with her roses and will they come out of it?

A. Unfortunately, these roses seem to have more dieback from the late frost we saw in April. If there is no green growth showing up on the main part of the plant, it is likely that it has died back. The roots would be shooting the new growth from the ground, but that is not going to be the same type of rose that you had there before because our roses are often grafted. The growth from the ground would be from the rootstock so it wouldn’t be the size and color of rose that was originally purchased. Unfortunately there is nothing that can be done about that. It might be time to go and choose some new rose colors for your garden.

11. A caller has a river birch tree that dropped its leaves in the summer last year. The leaves now are yellow and only the top half of the tree has leafed out this spring. They are 20 year old river birch trees. What would be causing this problem?

A. Look on the branches of the tree for signs of bronze birch borer. Some of the signs of this borer would be rippling on the branches or holes in the stem or branches. If you find the signs of bronze birch borer, you can treat it now with a borer spray or with a systemic insecticide.

12. A caller has a river birch tree that was growing in a clump and one of the trunks of the group died out. Should it be removed now?

A. Yes, any dead part of a tree should be removed as soon as it is noticed. A large part of a river birch, like this, could be hazardous if left standing after it dies. Unfortunately, when that branch is pruned off decay will likely begin but there is no way to prevent that at this point. This will likely be a large portion of the tree removed and that large of a pruning cut may not ever heal over entirely. When a branch doesn’t seal up, decay can get into the tree causing more damage. We don’t advise painting the stump with anything.

13. A question came in via email regarding a red twig dogwood. This dogwood is 4-5 years old and has never been pruned. Following the storms this week, some branches are falling over blocking a mowing path. Can those be pruned now? What should be done with it in the future?

A. Broken branches can be removed at any time. If these are just bending over, they could still be removed if necessary, but they may pop back up to their normal standing position. For future, red twig dogwoods should be pruned to the ground every 3-5 years to maintain that good red color on the twigs. They should be pruned in the late winter to early spring.

14. A lady called who has a Cranberry Bush Viburnum that has dead branches in it. Can those dead branches be pruned out now?

A. Yes, dead branches should always be removed when they are noticed. Check to ensure that these branches didn’t die due to Viburnum borers, if so, treat with a borer spray or systemic insecticide.

15. The last caller of the day has 2 different plants that have problems. A maple tree has brown specks on the leaves and they are falling off the tree. A Peony bush has leaves that are turning yellow along the edges of the leaf. What would be causing these two problems?

A. These both sound like frost damage. They will both be fine. The maple may drop all the damaged leaves and put on new growth.

Yard and Garden: May 12, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for May 12, 2017. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 28, 2017. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Dr. Paul Read, Viticulture Specialist from UNL

1. The first caller of the day called to ask when is the best time to take cuttings from grape vines and how should it be completed?

A: To take a cutting, when you cut off the dormant growth from the previous year, you can take those branches and put them in moist sand to get them to root. After the last spring frost of the year, you can plant those rooted branches outdoors. When you do this method, you need 2-3 buds on each branch. Put at least 1 bud into the ground and have 1-2 buds out of the ground for leaf growth. At this time of the year, you can complete the layering method of propagation. For layering, just bury a few of the longer branches that are still attached to the vine. Once they root, you can cut them from the main plant and replant somewhere else.

2. A caller has a 7 year old peach tree that is dropping leaves like it is fall. What would be causing this to happen and can it be corrected?

A: This could be abiotic stress due to unfavorable environmental conditions. It could also be from peach tree borer. Look along the trunk for small borer holes or sap oozing from branches or the trunk to know if it is the borer. If borers, spray the trunk with a fruit tree insecticide spray. If it doesn’t seem to be from insects, keep the tree healthy through a good mulch ring and regular watering as needed when natural rains are infrequent.

3. This caller has 2 concord grapes that were producing well last year but were taken by the birds before they could be harvested. How can you keep these birds away?

A: Bird netting over the plants to keep the birds out is the only good, effective method of managing birds in grapes.

This caller also wanted to know what is wrong with her peach trees? She has 2 peach trees that are 9-10 years old that now have an orange sap oozing from the trunk.

A: This would be from gummosis, a fungal disease common on peach trees. There is no real cure for this disease, it is just best to prune out the small branches that are affected and cut 6-8 inches below the infected area. Dip your pruners into a bleach/water solution between cuts to prevent further spread of the disease. It could also be from peach tree borers. In that case, use an insecticide labeled for use on peaches for borers.

4. A caller has a row of cottonwoods but there is one tree in the middle that always has yellow leaves rather than green leaves. What is wrong with it and can it be corrected?

A: This is most likely due to an iron deficiency in this tree. That can be corrected by having a certified arborist come in to do a trunk injection. The granules or stakes around the tree are not very effective. Often, iron chlorosis is a sign of other problems with the tree and may be the beginning of the end for the tree. That being said, many of our trees live many years after developing an iron deficiency and some just need an iron injection every 5+ years to live a long and happy life.

Tree hole for blog
Photo of the damage occurring to the Maple tree.

5. A caller has some maples that were recently pruned and the branches had a fungus and some white powdery substance in them when the branches were removed. What is wrong with them and do they need to be removed?

A: This caller emailed me with photos of the problem so I could see for sure what is wrong with the plants and if it can be corrected or if it is a safety issue. Unfortunately, this does look like decay in the tree. Decay within the interior of the tree can be dangerous for when it may fall, the tree is not stable when it has decay. I would guess that the tree has a large limb that was removed at one time and it was too big or improperly cut and now there is a large hole leading into the tree. I would get a certified arborist out to take a look and possibly remove the tree.

6. This caller has a cedar windbreak and would like to plant crabapples. Can crabapple trees grow near a cedar tree?

A: Yes, you can plant crabapple trees near cedars, just make sure that you select a variety that is resistant to cedar-apple rust to avoid having to spray annually to avoid the damage from cedar-apple rust.

7. A caller has a blue spruce tree that is 8 feet tall and was planted 14 years ago that died over the winter months. What happened and how can it be avoided in the other trees in the row?

A: This could be due to a canker which is a fungal disease that stops the flow of water and nutrients from the canker point outward and upward through the tree. If the canker occurred on the lower part of the trunk it would cause the tree to die. There is no cure for canker and no way to prevent it. It could also be due to a root issue that could have happened when the tree was planted or in the nursery. The tree may have a root that girdled the stem killing the tree or it may have been planted to deeply. When you remove the tree, look at the root system to see if this was the problem.

8. This caller has small brown circles in the lawn all around a tree. This problem occurs every year later in the summer in the same location of the lawn. What would be causing this and can it be controlled?

A: This is most likely due to summer patch, a common lawn fungal disease that occurs in the mid-late summer. Normally, this isn’t something that is treated for because it doesn’t occur in the same location every year, but for this caller, it does. Management practices in the lawn can help, such as mowing higher and doing core aeration to reduce the thatch layer in the lawn. If necessary, fungicides labeled for summer patch can be used from now until the end of June.

Summer Patch, L. Giesler turf update
Summer Patch in Kentucky bluegrass photo by Loren Giesler, UNL Plant Pathology

9. What is a better species selection than using Bradford pear?

A: Chanticleer or Cleveland Select are better options for pear trees than a Bradford Pear. Bradford pears tend to have narrow branch arrangement that leads to more broken branches from high winds and storms. These two options are better choices because their branches are wider when arranged on the trunk.

10. A caller has a maple tree that is half green and half a much lighter green color. What would cause this and can it be corrected?

A: The soil pH is higher on one side. A disturbance on the one side could cause it to have iron deficiency on the lighter green side. Try to spray chelated iron on the lighter green side to fix the problem.

11. When is the best time to start asparagus?

A: Spring is the best time, from March to April is prime time for planting asparagus crowns. Be sure to still wait 3 years before full harvest begins.

12. The final caller of the day had 2 questions. She had botrytis on her strawberries last year and sprayed a week ago. Does she need to spray again? Also, can an Annabel Hydrangea be planted in full sun?

A: For the strawberries, apply from 5-10% bloom until flowers have finished blooming. For more information see the Midwest Small Fruit and Grape Spray Guide from Midwest Universities including UNL. Annabel Hydrangea is one that prefers partial shade. I would avoid planting it in full sun on the South or West side of a building where it would get too hot.

 

Yard and Garden: April 28, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for April 28, 2017. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 28, 2017. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Dick Campbell, Owner of Campbell’s Nursery in Lincoln, NE

1. The first caller of the day has a Lilac that has bloomed in the past, but it isn’t blooming much. It has never been a reliable blooming shrub. What is wrong with it and how can it be fixed?

A: This plant was bloomed a few times in the fall, which would cut off the blooms for the following spring. However, this isn’t the only problem because for the past couple of years they have been better at timing their pruning. A late frost could have hit the blooms causing problems with bloom, it may reduce the overall bloom amount. Also, this could be a nutrient issue. A good fertilizer, such as bone meal, could be incorporated into the soil surrounding the plant to help with the nutrient availability.

2. A caller has ribbon grass that has died out in the center. This dead center has continued to get larger over the years. What can be done about that?

A: This plant needs to be divided. Many perennial grasses will develop a dead center when it is time to dig them up and divide them. The spring is a good time to do this for grasses. Iris plants will do this as well, they are best divided and replanted in the fall.

3. This caller has a weeping Norway spruce that is bending over heavily. Should it be trained to keep it more upright?

A: This is a typical growth habit for a weeping Norway spruce. They bend over more than some of the other weeping varieties. It would be good to put a small stake along the trunk of the tree to support it for more upright growth.

This caller also wanted to know what the timing was for spraying apple trees for Cedar-Apple Rust?

A: Now would be a good time. When the galls on the cedar rust have come out to look like a slimy glob in the spring rains it is time to spray. Those galls have just begun to open up and release the spores. For more information on cedar-apple rust, see this NebGuide.

Photo of Cedar Apple Rust Gall photo courtesy of Mike Lewinski via Flickr Creative Commons License

4. A caller has a cherry tree that has a split going up it and now it has sawdust around it on the ground.

A: Often we see insects in our plants as a secondary problem. What you are dealing with here, is most likely carpenter ants. They have come into the split in the tree and are making a nest in the rotting heartwood. The carpenter ants are not doing any more damage to the tree than what is already done. They can be killed by using an insecticide dust in the tree crack, such as sevin. However, the more concerning issue is the crack in the tree. If the tree is very large it may be a hazard. Tree removal may be necessary. If the crack is not very deep, it could be a frost crack which would be less hazardous.

5. Can you grow English Walnuts in Nebraska?

A: Yes, they can be grown here, it is most likely you will have to plant them from a seed as there aren’t many grown as plants for sale. Check with the Nebraska Nutgrowers Association for more information and seed/plant sources.

6. This caller has a blue spruce that is not growing well. It was planted 17 years ago and hasn’t grown more than a couple of feet in this time. What is wrong and can it be fixed?

A: The tree could be battling with too much brome grass growing around it and competing for nutrients and water. It would be beneficial to kill the brome grass and to add a mulch ring of 2-3 feet out and 2-3 inches deep around the tree to help reduce competition. This also could be a root issue that there would be no fix for. Often times, our trees are planted too deeply or grown in a container too long causing the roots to circle the tree. Once the tree is planted, there is no way to fix these conditions and the damage may not be present in the tree for 10-15 years after it was planted. This could be the case with this tree. Try adding mulch and ensuring proper irrigation through the growing season and it may come out of it.

7. A caller has a redbud that is 8 years old. The branches are dying and there are holes in the trunk. It seems that only one branch is still alive on the tree. What can be done for the tree? Or should it be removed?

A: The holes could be from borers that can be treated, but are often a secondary pest. If only one branch is left alive on the tree, it may be time to replant.

8. This caller is planting a new garden in an area that was a cornfield until this year. What do they need to do to the soil to plant in it?

A: Because this has been used as a crop field, I would advise a soil test to see where all the levels of pH, organic matter, Nitrogen, Phosphorus, and Potassium are at and to ensure vegetable crops will even grow in the soil that has been heavily planted for many years.

9. A caller is cleaning out dead and dying pine trees in a windbreak. Do the stumps need to be removed? What can be done to get it ready to replant?

A: If they are Junipers, or eastern red cedars, they can simply be cut off at ground level and they will not regrow. With some of our windbreak plants, they may need a stump treatment of 2,4-D or Roundup or a mix of the 2 products. If you are planning to plant a new windbreak where you removed these plants, it would be beneficial to grind out the stumps. If there is enough space, you can replant around the old stumps, just stay a few feet away from the stumps left behind if you don’t remove them.

10. What is the best care to give to seedling trees given to students for Arbor Day?

A: Grow the seedling in a pot for a year. When winter comes either plant the pot in the ground with heavy mulch or bring the container into the garage. Next spring, plant the seedling into the ground and protect it with fencing from rabbits and deer.

11. A caller wants to know how to control sandburs and where you can purchase milkweed plants?

A: Sandburs are controlled with crabgrass control products. As a preventer, using crabgrass pre-emergent herbicides will also prevent the germination of sandburs. If they have already germinated and are starting to come up, you can use a post-emergent herbicide for crabgrass such as quinclorac or Drive or Dimension. You should be able to find Milkweed plants at many local nurseries.

12. This caller has a white powdery substance on her peonies. What is it and what can be done for it? Also, she has a cherry tree that was severely damaged from deer, but now there are new suckers growing from the ground around it. Can those cherry tree suckers be grown into a new tree?

A: The white substance on the peonies would be powdery mildew. It is not very harmful to the plant. You can use a fungicide on it to control the spread of the disease. Also, make sure you cut off and remove the above ground growth that dies back in the fall to reduce the spores that overwinter for next year. The cherry suckers may not come up as the same species as you had planted and they may not be strong growing. Many of our fruit trees are grafted for a strong root system but desired traits from other trees. When suckers grow from the roots, you only get the type of tree that the main root system was and not the more desirable traits from the above ground portion of the plant. You can try it if you have room, but otherwise it would be best to start over from a new tree.

13. A caller put preen on his garden earlier this spring to stop the weeds. Now he is concerned if the plants he starts from seed this year will grow?

A: Unfortunately they will not grow where the preen is without extra care. You can either plant these plants from transplants or as seed in another location or in pots or you can till the bed to destroy the preen that is working as a barrier in the garden. Once you have gotten seeds to start growing in the garden, you can reapply the preen to reduce weeds later in the season.

14. A gentleman has holes around his house that are 1.5 inches in diameter and his tulip bulbs have been eaten off. What would cause these holes and how can the “critter” be managed?

A: This could be from either 13-lined ground squirrels or from voles. If it is voles, there would be runs in the lawn. Place a couple of snap-type mouse traps perpendicular to the runs in the lawn to manage the voles. If it is 13-lined ground squirrels, see this publication from UNL.