Yard & Garden: July 24, 2020

This is the Q&A for the Yard and Garden show for July 24, 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: Bob Henrickson, Horticulture Program Coordinator for the Nebraska Statewide Arboretum

1. The first question of the show was regarding peppers that are in a garden next to a soybean field. The peppers are wilted now and the caller was wondering if this was from herbicide drift?

A. Herbicide injury doesn’t typically look like wilted plants, that will cause cupped leaves or leaves that are deformed. If the plant is wilting, it could be from root issues. Make sure that the soil is dry before watering again. It could be from too much water.

2. The second caller is also struggling with his pepper plants. They seem to be quite wilted as well. The wilting seems worse during the heat of the day. Could it be something else?

A. With more information, it seems that both pepper plants seem to be having troubles with heat stress, which is common this year, across the listening area. There really isn’t much to do to fix heat stress, water won’t necessarily help with heat stress. Give them time and they will pull through and be fine. Keep them watered, but don’t overwater.

3. A caller has a linden with skeletonized leaves. What is the problem?

A. Japanese beetles are likely causing the problem. You can use sevin or other insecticides. They will likely not kill the tree, but will make it look bad. Most of the damage for this year could be done already. Look at the tree for more green beetles with copper-colored wings or elytra. If you don’t see many beetles, forego the spraying for this year.

4. This caller has bagworms on her cedars in the pasture. Will those move to her windbreak trees this year?

A. They should be in their location for the year now. They typically only move around when they are very small, at this point in the year they shouldn’t move much.

5. When is a good time to cut peonies back?

A. The fall is the best time to cut peonies and clean the plants up. They will turn brown in late September to early October, that is when they should be pruned back. This allows the plants to build sugars all summer to help with early spring bloom next year.

6. The final question of the show was from a caller that has a weedy tree in her yard that looks like a palm tree. What could that be?

A. Without seeing the tree it is hard to tell for sure what it is. It could possibly be a tree of heaven or a pokeweed plant. It was advised that she send a picture to the Extension Office.

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

Yard & Garden: July 10, 2020

This is the Q&A for the Yard and Garden show for July 10, 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: Justin Evertson, Green Infrastructure Coordinator for the Nebraska Forest Service

1. The first question of the show was from a caller who has a 20 foot tall blue spruce that the top 5-6 feet is turning brown. What caused this and what can be done about it?

A. This is likely from a canker. Canker fungi are common in blue spruce trees and will often cause the top portion of the tree to die. The dead area should be cut out but then you will lose the apical dominance and the tree won’t grow upward much after removing the terminal bud. It will die back to a certain spot then stop, the rest of the tree will remain healthy.

2. This caller has tomatoes with leaves that are curling. 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.

3. A walk-in listener has an row of arborvitae that have developed brown spots in them this summer. What is causing this?

A. Arborvitae struggle with the extreme temperatures that Nebraska have. The damage looks mostly like environmental stress. Keep them sufficiently watered, but don’t overwater. Keep them mulched in. Depending on the amount of dieback, they may survive.

4. This caller planted broccoli in mid to late May, now the leaves are developing holes and there is no head developing yet. What is wrong with it?

A. It is likely that the broccoli was planted too late and may not develop the head. Broccoli is more of a cool season plant, they don’t grow well in this heat. The holes are likely due to one of the looper caterpillars that are common on broccoli. Sevin will help with that.

5. A caller has a large pine tree that is looking dead, quite suddenly. It is losing a lot of needles and has turned brown. What is wrong with it?

A. This is likely due to pine wilt disease. There is no cure for the disease and no way to prevent it prior to infection. The tree should be removed.

She also wondered if she could still spray for bagworms?

A. We are quickly nearing the end of the time frame for spraying for bagworms. They are best sprayed when the bags are 1/2 inch in length or less. As the bags get too big, the sprays become less effective. Spraying soon should be ok, but if you wait too long you may not see 100% coverage from the sprays. Use Tempo and spray in the next week for best control.

6. This caller has an apple tree that didn’t bloom this year and the leaves look bad. Will it survive and is there anything to do for the tree?

A. The frost likely injured the blooms. They will not produce apples this year if that is what happened. The plants will still survive. After discussion, it seems that the apple trees have rust on them, which is common. The spray time has passed. You can spray the trees next spring with a copper fungicide for the rust or use an orchard fruit tree spray through the season next year to work on insects and diseases in the trees.

7. A caller has a forsythia and a red twig dogwood that have grown too large for the area. When can they be pruned so they aren’t blocking windows?

A. If flowers are not critical, these plants can be pruned most anytime. Pruning right now would reduce the flowers for next year, since they are mostly set on for next year already. However, the best time for pruning the forsythia is just after it has finished blooming and the dogwood would be in the late winter. They can both be rejuvenated by pruning all the way back to the ground, about 6-8 inches above ground. The rejuvenation pruning should be done in the fall.

8. This caller has tomatoes and cucumbers with spots on the leaves. Is this a fungus and should a fungicide be used?

A. This could be from a fungus, it is hard to tell without seeing the plants. However, it is not the same fungus, these would have different types of fungi. Fungi are typically host specific. If there are just a few leaves that are damaged, those could be removed and destroyed. If the plant seems to have a lot of damaged leaves, a fungicide could be used if desired. Watering from below on the plants or earlier in the day if using overhead irrigation can help reduce the spread and incidence of the disease. If using a fungicide, be sure to read and follow the label and follow the PHI or pre-harvest interval. The PHI is how many days to wait for harvest after an application of a pesticide is made.

9. A caller has 3 river birches and a corkscrew weeping willow. After the late frost this spring, there are branches that are now dead, with no leaves. Will these plants survive?

A. It is unlikely that they will survive if they are not green now. It is likely that the late frost injured them and they cannot recover. If it is a few select branches, you might be able to remove them and the tree may be ok, but if the majority of the canopy has no green leaves on it, they will not survive. These plants can struggle with the extreme temperatures of Nebraska.

japanese beetle JAK582
Japanese Beetle, Photo from Jim Kalisch, UNL Entomologist Emeritus

10. What can be done about Japanese Beetles?

A. The plants that the Japanese beetles are found on can be sprayed with carbaryl, bifenthrin, or chlorantraniliprole. For organic options neem or pyola can be used. Don’t use the traps, they will bring in more beetles than what you already have. Grub controls can help a little with the population size. Be sure to avoid spraying the flowers of any plants.

11. This caller has a wild plum thicket along their driveway. It is spreading too much into the driveway. When can it be pruned back to avoid scratching cars that drive by?

A. The areas of the plum thicket that are creeping out of normal growth can be cut back most anytime. They are a tough plant and should be fine.

She also has a vegetable garden that is not growing well this year. It is the same location that she has gardened for years, but the plants just are not doing well. Can she add manure to it and if so, when?

A. You can add manure to the garden. For food safety guidelines, fresh manure should be applied 120 days prior to harvest of any crops, so we advise adding manure in the fall. However, since this has been a good garden space, I would suggest doing a soil test prior to soil amendments to know exactly what the problem is and know how to fix it.

12. A caller has a silver maple that lost limbs and has started to split from the recent storms. Can the tree be pulled back together with a cable?

A. It is best to work with an arborist on this, to ensure it is done correctly. However, the tree may be too large for a cable to effectively help with the split. It may be time to remove this tree. Silver maples are prone to decay from wounds such as this, it is likely the beginning of the end for the tree anyway.

13. The final question of the day is about a black hills spruce that is browning sporadically on the ends of branches throughout the tree. What is wrong with it?

A. This tree could have freeze damage on the tips of the branches from the late frost and snow this spring. It could also be from a disease called sirococcus or needle cast. It would be too late for treatment with either of these diseases, but they shouldn’t kill the tree. The brown areas can be pruned out and next spring, it might be good to spray the tree with a fungicide.

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

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 12, 2020

This is the Q&A for the Yard and Garden show for June 12, 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 tomatoes that only grew to about 1 foot tall and then they died back from the top. What is wrong with them?

A. It could be that they need to be watered more effectively. He has the plants mulched with grass and is watering, but just using a hose-end sprayer. When just watering with a hose like that the top couple inches of soil get wet then it spreads out rather than down, so the plants aren’t getting enough water to their roots. It could also be from a disease, but it is hard to tell from just a description.

2. A caller has watermelon radish plants that are going to seed. Can she cut the flower stalks off so they continue to grow? The radishes are not very large yet.

A. These plants are not going to grow much longer. When we get to hot weather the cool season crops will go to seed or bolt and will not live long, radishes are one of those plants. She said she had to replant later in the year due to frost damage in late April/early May, that is just too late to plant radishes for a good crop. She could try again in the fall or plant earlier next spring.

3. A caller has an American elm tree that has a few branches that are dying off. He has cages of rabbits underneath the tree and wondered if too much nitrogen was being applied to the roots or if the roots are reaching up to under the chicken coop with high nitrogen?

A. It is more likely that this tree has developed Dutch Elm Disease and will likely die. 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.

4. This caller is actually from Oklahoma, but was doing work in the area to call in. He was wondering what we do for squash bugs?

A. Squash bugs can be difficult to control in a garden and most of the time once they are in your garden, they will always be there. For chemical controls, sevin, eight, or bifenthrin are all labeled for use in the vegetable garden. Be sure to watch the PHI, pre-harvest interval, or amount of days to wait from application until harvest. For squash bugs make sure you are spraying thoroughly on the underside of the leaves where the eggs are laid to kill larvae just as they emerge. You can also squash the copper-colored, football shaped eggs as you find them on the underside of the leaves. Be sure to clean up the garden in the fall to eliminate the overwintering site.

5. This caller had 3 questions. First, when and how short can a spirea be pruned?

A. It is a spring blooming spirea, so it should be pruned within a few weeks after blooming has completed for the year. Up to 1/3 of the plant can be removed in one season. So if it is 3 feet tall, you can remove 1 foot of the growth. Be sure to prune back to a side branch. Continual shearing will leave heavy growth at the base of the plant with spindly growth on top. Spireas can be renewed with a rejuvenation pruning where it is cut back to 6-8 inches above the ground. This should be done in the fall and not every year. You will not see blooms the year following a rejuvenation pruning.

How do you prune lilacs? It is overgrown.

A. If the lilac is overgrown, it can be pruned through a rejuvenation pruning in the fall, like suggested with spireas. Otherwise, it should be pruned within a few weeks after blooming has been completed in the spring.

His final question was about tree black walnut. The tree was pruned at a random location mid-way through the branch. It has now died back further than where it was pruned. What is wrong with it?

A. Be sure to make a good pruning cut. Branches either need to be pruned back to the trunk, just outside of the branch collar, or to a side branch. The side branch needs to be at least 1/2 the size of the branch being removed.

6. A caller has poppies that she received from the Yukon. These poppies are blooming now and she wants to dead head so they continue to bloom, but she also wants to save the seed to start some new plants. Can she cut the flower heads off before they fully dry to save the seed?

A. The seed needs to be allowed to fully mature on the plant. So, unfortunately, you will have to choose between dead heading and allowing the seed to mature on the plant. If they are picked too soon, some may germinate, but the rate will be low.

7. An emailed question regarding the listeners garden which was hit by herbicide drift. Will the produce from this garden be safe to consume?

A. There is no way to know for sure when or if the produce will be safe to eat. It is better to throw it out and start over when in doubt.

8. This caller was curious about collecting seed from winter onions, or walking onions. She tried last year but they didn’t grow at her house after she took the above ground bulbs from her sisters plants. What does she need to do differently to get these onions to grow?

A. These also need to be allowed to fully mature on the plant, like the poppies. The stems with the above ground bulblets on them will dry up and fall over. When they are falling over the bulblets are mature and can be picked up and planted in new locations. If the bulblets were picked off the plant prior to this, they were not fully mature and wouldn’t develop into new plants.

9. A caller has oak trees that the branches are dying from the bottom up. What can be done?

A. These are likely pin oak trees and it is very common in pin oak trees. The lower branches could be dying due to lack of sunlight. It could also be due to a few diseases. If the branches are dead with no leaves, they should be removed to keep them from falling. If this continues, a sample could be submitted either by photo to me or a sample to the diagnostic lab at UNL, linked above.

10. This caller has tomato plants that were cut off at the ground level but the plant was left behind. What caused that? How can this be stopped?

A. This was likely due to cutworms. They can be managed by using sevin or diatomaceous earth around the base of the plant when they are planted. You can also wrap the base of the plant with aluminum foil to prevent feeding. This caller took the plants inside the next day and placed them in water and in soil to try to re-root them, it worked for some. Great idea, if caught early enough!

She also wondered if diatomaceous earth is effective for squash bugs?

A. It would not be as effective for squash bug adults. It can be used for squash bug nymphs.

Bagworm4
Bagworm

11. A caller sprayed his evergreen trees with Tempo to treat for bagworms and it rained just a few hours later. Will he need to respray?

A. The label states that it is rainfast after 24 hours, it is likely that this application was mostly washed off. The label also states that it can be reapplied every 7-10 days, so it would be best to wait about 7 days before reapplying. It would still be within the timeframe for spraying bagworms at that time.

12. This caller has been able to hand-pick bagworms off of her small tree through the year. Does she also need to spray?

A. If you are able to continue to pick the bagworms off as you see any new bags form, you wouldn’t have to. If you see a large amount of small, black caterpillars or if a large quantity of bags form on the tree, you can spray.

13. How often can you spray Eight to control squash bugs?

A. Remember to always read and follow the label when using pesticides. It would likely be fine to spray every 10-14 days through the season, but one label I looked at said every 3 days if necessary. Just be sure to follow what your label states and also follow the PHI, pre-harvest interval, or amount of days to wait from application until harvest.

14. A caller has an oak with old scars where limbs were removed by previous home owners. One of the wounds is weeping. What is causing this weeping? What can be done about it?

A. This is likely due to a bacterial infection of the heartwood, called wet wood disease. Those pruning scars did not fully seal over and it has allowed the bacteria to enter the tree. It is minimal damage to the tree and won’t kill the tree. There is nothing to do to stop the weeping, but again it doesn’t really hurt the tree.

15. The final question of the day was from a caller who has cucumber plants with leaves that are drying up and dying. What is causing the browning which starts on the outside edge of the leaves? Can anything be sprayed on the plants to stop the damage?

A. This is likely either environmental stress or a slight fungal disease. The environmental stress could be due to the heat or drought stress if they aren’t receiving sufficient irrigation through this hot, windy weather. It could also be from a fungus, there are many that affect cucumbers. A fungicide, such as copper, could be used to reduce the spread. Without a picture, it is hard to determine for sure what is affecting these plants.

*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 29, 2020

This is the Q&A for the Yard and Garden show for May 29, 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 tomato plants that now is developing “skinny” leaves. What is wrong with them?

A. The leaves are skinny and deformed. 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.

2. This caller has a very large hosta. When can it be divided?

A. Early spring is the best time to divide hostas, once they have emerged from the ground but before the heat of the summer. It might be a little late to divide the plants this year due to the hot weather expected next week. If they are divided now, be sure to keep them well watered.

3. When can oaks and maples be pruned?

A. The new pruning recommendations show that pruning is best if done in late spring, so late May to early June for Nebraska. Now would be a good time for most trees, however, oaks are susceptible to oak wilt if pruned during the summer months. It is best to wait until fall, September or October, to prune oak trees to avoid this disease. Maples, can have a heavy sap flow in the spring, they can be pruned now, but may leak sap, sometimes large quantities. They would be better to prune in the fall also.

4. A caller was going to use Grass-B-Gon on some weeds she recently hand-pulled to reduce the hand-pulling in the future. How long should the regrowth be before she applies the grass killing product to her landscape beds?

A. As long as you start to see some new, green regrowth, the product should work. According to the label, it should be applied anytime weeds are actively growing, which would be when you see them green up again around your landscape plants.

5. This caller is on her second round of planting tomatoes and they are turning yellow again. She planted the first in late April and then again recently. In the new planting one plant is starting to turn yellow. She is using straw mulch on most of the plants but is using grass mulch on the one plant that is turning yellow. What is wrong with her plants?

A. The first round of plants were planted too soon and we saw quite a bit of cold weather later in the season this year than many other years. She did cover the plants on the sides, but left the top exposed. Frost would have settled down onto the plants and killed them. The new plants are doing fine except the one plant that has grass clippings on it. The lawn has been treated with broadleaf weed control as well as crabgrass control this year. The labels will tell you not to use the clippings on the garden for the season or for a period of time. If that isn’t being followed and this is the one plant that is looking bad, I would assume that the grass clippings are the problem. Be sure to use clean grass clippings or use straw for all of the plants.

6. A caller pulled 3 mature barberry bushes with a pickup truck and then decided to replant them after all. What should be done to keep them alive? Should they be fertilized?

A. Pulling these plants out with a pickup truck and chains would have drastically damaged the cambium layer which can reduce the flow of water and other nutrients through the plant. They were also kept out of the ground for a week before being replanted. These plants could pull through if they are tough, but you will need to make sure they are kept moderately watered. Don’t overwater, but don’t allow the plants to dry out either. A slow trickle for about 10 minutes a couple of times per week will help to rebuild the roots. Do not fertilize them. Fertilizing a stressed plant can further stress the plant. Only time will tell if they can survive.

7. This caller has lilacs that are looking bad and didn’t bloom well. What can be done to help them? When can they be pruned?

A. Sounds like this lilac is in need of a rejuvenation pruning. This is where you cut the plant off about 6-8 inches above the ground level to rejuvenate the growth. It will reduce insect problems and push new, young growth to provide better blooming and have a healthier plant. This can be done in the fall for best results.

8. A caller had bagworms on her cedars last year. She also noticed a lot of praying mantis egg cases, she knows they are a good predator.  Are the praying mantis’ helping to control the bagworms?

A. Praying mantis’ are not a major predator of bagworms. They prefer feeding on aphids and others.

She also wondered about her forsythia that was injured by the late frost this year. It didn’t bloom this year and she had to cut back some of the branches. Will it bloom next year now or did this damage the blooms for next year as well?

A. The blossoms are set on the new growth that will form this summer. As long as they are pruned back within about 3 weeks after their bloom period, they will still bloom next year. This is why we prune forsythia just after they bloom rather than in the late winter. This forsythia should still bloom next year.

She had one final question, how can she control a clover-type weed growing profusely in her iris beds?

A. This will be difficult to do without harming the iris plants. She could spray with Roundup using a piece of cardboard as a barrier between the weeds and the iris plants or she could use the “glove of death”. 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 bindweed to kill it.

9. What can be done to control elm saplings in a windbreak?

A. You can go through and cut off the trees and follow that up with a stump treatment using either 2,4-D or a glyphosate product, such as Roundup. The Roundup would be better this late into the year to avoid volatilization issues from the 2,4-D in the heat. 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.

10. A caller planted grass in the spring. It is getting to about 2 inches tall now. When can he spray the weeds coming in with the grass?

A. You should wait until after 3 times mowing the new lawn before any herbicides should be applied to the grass to avoid injury. However, by that time, it will be too hot to use any 2,4-D products, which will turn into a gas and move to non-target plants and injure them in temperatures above 80-85 degrees. It would be better to just wait it out and spray in the fall to manage the weeds after the turf is more established. The fall is a better time to treat for perennial broadleaf weeds because it is when the plant is taking nutrients back into the root system and it will take more of the herbicide with it. Spray twice in the fall, once in mid-September and again in early to mid-October.

11. This caller has a hydrangea that didn’t look like it was going to live through the late frosts this spring. She did notice that it is finally coming up but it is only about 3 inches tall and is setting blossoms on. Should she remove those or let the plant bloom at such a small size?

A. It would be best to remove those blooms to allow the plant to grow a bit more before trying to bloom. All the energy in that plant would push into flower production, at such a small size, it would be best to allow the plant to build leaves and the root system to help it so it comes back next year.

12. A caller wants to know what to do to keep iris blooms from falling over?

A. Sometimes if the flower is too heavy it can fall over a bit. There are metal rings you can purchase to put in flower beds around plants that fall over to keep them upright, but nothing else will work for this. The flower is just too heavy for the stalk.

13. If branches on a tree or shrub are already dead can they be pruned off now?

A. Yes, dead branches should be removed as soon as they are noticed to prevent injury or damage from a falling branch.

14. The final call of the show asked if they should be fertilizing lilacs that were planted 3 years ago?

A. Fertlilizer doesn’t need to be used on plants that are growing just fine. Most trees and shrubs can get the nutrients they need to survive from our soils. The best thing is to do a soil test prior to adding any soil amendments, nutrients can build up to a too high level which can also damage the plant.

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

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.

 

Vegetable Gardens

Spring is a wonderful time of the year! After a long, cold winter, it is always so wonderful to be able to get outside again and start working in our gardens. And there is nothing like fresh produce from your own garden during the summer months.

Garden location

Make sure that the soil is dry before you work the garden or plant any vegetables. Planting into mud can compact the soil and disrupt the growth of plants. If you don’t have the space or can’t dig up the lawn for a traditional garden or are unable to work on the ground, you can use a raised bed or even garden in containers. If you do either of these non-traditional methods, use potting soil rather than digging up soil from the backyard due to nutrient values, compaction, and water draining issues.

Locate your garden where it will receive at least 6 hours of sunlight per day. The majority of the sunlight hours should be in the afternoon when the sun is more intense. Also, choose a location that is near a water supply and is easily accessible for you to get to often.

Plants

When choosing what to plant in your garden, think about the things that you and your family enjoy eating most and plant that. If you are new to gardening don’t take on too much the first year. Also, be sure to space your plants correctly. Understanding how big plants get can help plan out the garden space to make sure everything doesn’t run together. Messy gardens are hard to maintain and diseases can spread faster in these environments where the plants are too close together. The seed packet or plant tag will tell you how far apart to space your plants, be sure to stick with the recommended spacing.

Cool season crops such as peas, potatoes, carrots, radish, kohlrabi, broccoli, cabbage, cauliflower, lettuce, and spinach can be planted in March-April, depending on what you plan to plant. Warm season crops such as tomatoes, cucumbers, peppers, eggplant, corn and beans should be planted in early May, or after our last frost of the spring.

Plants such as carrots, radishes, lettuce, spinach, corn and beans should be planted as seed straight into the garden. Plant tomatoes, peppers, and eggplant from transplants that were started early in a greenhouse or in your home. Plants including zucchini, squash, melons, and cucumbers can be planted either as seed or as transplants.

Plant Care

Gardens need about 1 inch of water per week for best growth. Soaker hoses and drip irrigation are the best options to reduce diseases, but overhead irrigation can be used. If watering through overhead irrigation, it is best to water early in the day, to allow the garden enough time for the leaves to dry out before nightfall.

Vegetable gardens should be mulched in some way to manage weeds. Grass clippings make a good mulch as long as the lawn hasn’t been treated with any herbicides. If grass isn’t available or isn’t an option for you, you can use straw, newspaper, or wood chip mulch on the garden as well. Preemergence herbicides such as Preen can be used as long as it is labeled for use in the garden around your plants. Don’t apply preen around your seeded plants until they have emerged.

Plants like beans and peas will need a trellis to grow properly and tomato plants and other tall, bushy plants should be grown in a cage to keep them from falling over. Vining crops, such as cucumbers, can be grown on a trellis if desired. This will keep the plants up with good airflow to help reduce disease and it will make harvest much easier.

Yard & Garden: April 24, 2020

This is the Q&A for the Yard and Garden show for April 24, 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 day had his yard sprayed for broadleaf weeds yesterday. How long should he wait before overseeding the lawn?

A. According to the label of Trimec, grass cannot be reseeded until 3-4 weeks after applications from the product. Any 2,4-D product would be similar. At this point, it would be best to wait until the fall to overseed the lawn, because that late in the spring would be hard to get the turf established. Be sure to tell your lawn company not to spray it in the fall until after the new grass has been mowed 3 times in the fall.

2. Can you start sweet potatoes from the sprouting sweet potatoes purchased from the grocery store?

A. You can, but they may not grow quite as well as desired. The varieties in the grocery store may not be as hardy as some of the varieties from the garden centers.

3. This caller is planting cucumbers, zucchini, pumpkins and other cucurbit plants. How far apart do they need to be planted to prevent cross-pollination?

A. The cross-pollination affects the produce in the following year, not the current growth period. The produce on the plants this year will be fine, but if they cross-pollinate, the fruits produced next year may not be true to the variety you are saving seed from. They also have to be in the same species to cross-pollinate, and cucumbers and zucchini are not.

4. A caller has rhubarb plants that are producing seed heads. Why is that happening so early and should anything be done about that?

A. The cold temperatures from last week 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.

5. This caller has a rose garden that has chives coming up among the roses. What can be done to manage the chives and not harm the roses?

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 leaves of the chives to kill it. This will likely take multiple applications over multiple years to completely rid the garden of the chives, but this is best to not harm the roses.

6. A caller is wondering what the best method is for transplanting 5 foot tall peach trees?

A. The best time for this would be in the dormant period, either in the fall or late winter months. Be sure to get as much of the rootball as possible.

7. This caller has planted the Hairy Balls plant and now grass is growing up among the plants. Can Grass-B-Gon be used in these plants to kill the grass and not harm the plants?

A. It should be fine, Hairy Balls plant is in the milkweed family which is not a grass. It would be best to avoid spraying directly on the foliage of the desired plant to ensure limited exposure.

8. This caller started lettuce, spinach, and some herbs before the snow. They have not come up yet. Will they be ok or should they be replanted?

A. Give the plants a little more time to see if they come up yet. If they hadn’t germinated yet, they should be ok, but the soil temperatures were too cold with the snow and freezing temperatures last week for them to germinate. If they don’t come up soon, you can try to reseed or move these crops to a fall garden because we are going to start getting too warm soon.

He also wanted to know if his strawberries will survive? He planted them as roots prior to the snow, and they had no real above-ground growth prior to the snow.

A. Those should be fine, because they hadn’t started to grow yet. The roots should have been protected enough to survive.

9. A caller has strawberries that are growing in a raised bed. The strawberries in the center of the bed seem to have died out. Can she move some new starts from the outside edge to the middle now? Also, what should they be fertilized with? She has some 11-15-11 can she use that?

A. Yes, it is ok to move established plants now to fill in the bed better. The fertilizer she has would be fine to use. Just be sure to follow the label instructions on applications.

10. When can a magnolia tree be pruned to allow a lawnmower underneath?

A. The timing for tree pruning has shifted a little recently due to new research. The International Society of Arboriculture has moved the time frame to correspond with the spring growth flush which would be May through early June for southeast Nebraska. This allows the tree to seal up the wound faster with less disease and insect issues.

11. This caller has snowball bush hydrangea plants that are spreading and growing into the lawn. Can he divide the plants to move the plants that are spreading into undesired areas to grow in better locations?

A. Yes, either do it now or in the fall. When you dig them up, they may be attached to the main plant, just prune that connection off to move them.

12. A caller has iris plants that had pushed new leaf growth and then were hit by the snow and the tips of the leaves are brown and discolored. What should be done with that?

A. The plants will be fine. It might be best to wait until a few more leaves appear that are not brown, then the entire leaf that is brown can be removed. Wait to get more new leaves to avoid removing all the sugar producing leaves to be removed now.

13. What are some good plants for pollinators? Where should these be purchased?

A. Good choices would include butterfly bush, butterfly milkweed, milkweed, goldenrod, coneflowers, bee balm, sunflowers, coreopsis, and many more. They can be purchased at local nurseries and garden centers. Pollinator seed mixes can be found at some seed supply companies, including Stock Seed Farms in Murdock, NE.

14. The final caller of the day planted pampass grass it started to green up, but now after the snow nothing seems to be alive. Will these plants be ok?

A. Give the plants a couple more weeks to see if they will regrow. The roots should still be fine and it is likely that they will regrow, but if nothing in a couple of weeks, there would still be time to replant these.

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