Now that fall has arrived and we have hit some very cold temperatures at night, it is time to clean up our gardens for the winter. Some things should be done this fall, but some can be left until spring. Here are a few things to do now to put your gardens to bed.
Annual flowers can be cleaned up in fall because they die with a freeze. Perennials are best left standing until spring but some can be cleaned up now. It is nice to leave the plants over the winter for added interest and to provide food to birds. Plants such as roses and butterfly bushes that have hollow stems should be left standing and not pruned back until next spring. Precipitation can get into the hollow stems and freeze and thaw through the winter, which could crack the plant crown and lead to death. Leaving plants standing through winter will protect plants with hollow stems or with moderate hardiness to our zone. If you do chose to leave your perennial plants over the winter, be sure to wait until we are past our last spring frost before removing the plant material next spring, even if the plants green up underneath. The plant material does act as insulation and if removed too soon the plant will be more exposed to late winterkill. If removing plant material this fall, wait until it turns brown and replenish mulch to protect it over the winter. Mulch can be added up to 4-6 inches over the winter months, reduce back to 2-3 inches deep during the growing season.
People often think about pruning trees in fall. However, this isn’t the best time of the year to prune them. The optimum time for tree pruning is April, May, or June because at this time the tree can seal up the wound quickly while it is actively growing. If your tree needs to be pruned this fall, wait until the leaves have fallen from the tree to allow the tree to go completely dormant before pruning. If you are pruning an oak tree, the dormant period is the best time for pruning to avoid damage from oak wilt. Pruning evergreen shrubs is best done after they are fully dormant to avoid damage from winter injury. As for flowering shrubs, if it blooms in the spring, prune it after it blooms. If the shrub blooms in the summer, bloom in the late winter such as in February and March.
Now that our vegetable plants have died due to cold weather, it is time to clean up the garden. If any of your plants had disease or insect issues this summer, it is best to remove those plants and destroy them, don’t compost them. This will reduce the chance of seeing the problem again next year. Also, removing the plants from the garden at the end of the season will remove the overwintering site for insects found in the garden. Cleaning tomato cages and fences upon removal will also help remove the disease spores from the garden for next year.
After removing the plants, you may want to till your garden. If you plan to add fresh manure to your garden, that should be added in the fall rather than in the spring. So you can till your garden, add manure, and till it again to incorporate the manure into your garden soil for reduced compaction and improved organic matter content. If you till in the fall, add a layer of mulch to the garden to keep the soil from blowing off site during the winter. Grass clippings from a lawn that wasn’t treated with herbicides this year make a great mulch for the winter. You can till that back into the soil next spring before planting again.
This is the Q&A for the Yard and Garden show for July 5, 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: Laurie Stepanek, Forest Health Management Specialist from the Nebraska Forest Service
1. The first question of the show was curious about bagworms. He needs to spray the trees in his backyard but he has a coy pond nearby. Will the sprays harm the fish in the pond?
A. It would be best to use Bt on the bagworms here to ensure that if sprays get into the pond it will not harm the fish. Bt is a product that affects only butterflies and moths and won’t harm other insects or wildlife. Bt works best on young, newly emerged bagworms, but there would still be time for that product this year.
2. A caller has willow trees that are growing on a dam for a pond. How can they be controlled?
A. Rodeo or Garlon 3A are the 2 products listed for managing woody plants or annual and perennial weeds in or around water in the Weed Management Guide from Nebraska Extension.
3. This caller has garden plants that were chewed off by rabbits. Will these plants regrow or are they dead?
A. If there are still a few leaves left on the plant they might still regrow. However, if there is really only a stem and a tiny leaf or two, they likely won’t regrow. It is getting quite late for replanting, so it might be best to just wait and see how they regrow.
4. A caller has an apple tree that broke off at a split in the tree in a storm. Now there is a hole in the tree. What can be sprayed or put into that hole to prevent further damage?
A. It is not recommended to fill holes in the tree because that can be harmful when the tree does need to be removed. It also will not stop decay that is occurring in the tree. Decay is a fungus and it will proceed through the tree even around a fill agent. If the decay is a problem in the tree, the tree may need to be removed before it becomes a hazard.
This caller also has a maple with dead branches in the top of the canopy. What would cause that?
A. Top dieback could come from a number of factors. It could be from a canker disease that occurs on stressed trees. Canker diseases will kill branches from the point of infection outward on the branch. The only cure for a canker would be to cut out the branch below the canker. Top dieback could also be from borers or a root issue. Borers come into a stressed tree and will cause decreased flow of water and nutrients through the tree causing the top of the branches to die. If more soil is added to roots, causing decreased airflow to the roots, top dieback can occur. Root issues such as damage to the roots or a girdled root can also cause top dieback in the tree. Root issues cannot be fixed. If you notice borer holes, you can use a systemic insecticide containing Imidacloprid, such as Merit.
5. A walk-in listener wants help with identification of a weedy grass species that he is having trouble controlling.
A. This looks to be annual bluegrass, which can be difficult to control. Use pre-emergent herbicides such as Drive or Pendulum in September or use Tenacity as a post-emergent herbicide in the spring or summer. For more information, view this Turf iNfo on Annual Bluegrass Control.
6. This caller has maple trees that have limbs reaching out over his house, some of the limbs are dead. When and how far should these limbs be pruned to ensure they don’t fall on the house and cause problems?
A. It would be best to find a Certified Arborist to do this to ensure it is done correctly and to avoid damage to the house. Remove all dead branches. When shortening branches, cut back to a side branch that is at least 1/2 the size of the limb you are removing. Anytime would be ok, but the best time for a maple is later in the spring, to avoid heavy sap flow if pruned in the early spring or late winter.
7. A caller accidentally spilled hydraulic oil from his tractor onto his lawn. There is now a dead area in the soil. What is a quicker way to get grass growing back there other than to wait?
A. It might help to dig out the soil in that area and replace it with new topsoil. Dig out around the area of dead grass and dig 4-6 inches deep. It would be best to just wait until early September to do this so that it can be reseeded right away.
8. This caller wants to use Roundup around the base of fruit trees to kill grass. Should regular Roundup be used or could Extended Control Roundup be used?
A. Use basic Roundup that only contains glyphosate in this location. The Extended Control Roundup contains Imazapic for longer control and shouldn’t be used around fruits and vegetables. The label for the Extended Control Roundup states ‘Do not use for vegetable garden preparation or in and around fruits and vegetables’. Always read and follow labels of pesticides.
This caller also wanted to know what is wrong with her apricot trees, the fruits seem to be rotting as they fall from the tree?
A. This is likely due to brown rot. Next year, use orchard fruit tree sprays through the growing season. The orchard fruit sprays should be used every 10-14 days through the growing season, except during the bloom period and when ready to harvest.
9. The last caller of the day wants to know if he can eat the fruits off a purple leaf sand cherry? Also, can he shear it or is it too old to start that now that it is 5-6 years old and hasn’t been sheared yet?
A. The berries are not eaten from purple leaf sand cherry, this plant is more for ornamental value. These fruits are scavenged by birds instead. This is also a plant that won’t grow well if sheared. It is best to just selectively remove branches back to side-shoots to reduce the size.
*Disclaimer - Reference to any specific brand named product does not constitute endorsement, recommendation, favoring or implied criticism if similar products are not mentioned by Nebraska Extension in Gage County. Identifying specific pesticides are for the convenience of the reader and are generally most commonly available. Always read and follow the pesticide label.
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.
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.
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.
This is the Q&A for the Yard and Garden show for April 26, 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: Roch Gaussoin, Extension Specialist for UNL Agronomy and Turf
1. The first caller of the show recently applied a Weed-B-Gon product that contained crabgrass control. Now he wants to fertilize, but it is a fertilizer and crabgrass control together. Will it be harmful to put the crabgrass control on twice this spring?
A. That should be fine and you won’t see any injury from applying the crabgrass control twice this spring. You won’t need to apply any additional pesticides for the lawn this year. Next year, it would be better to do a little more planning ahead so you don’t apply the chemical twice so close together. This is just additional pesticides in the environment that are not necessary, so be careful with that in the future.
2. A caller is bringing in topsoil on a new build site. He needs to overseed, but is it getting too late to do that yet this spring?
A. Seeding the lawn will have the best results if done in the fall, but spring can get a good start on a new lawn. The weather will be the problem to lawns seeded too late this year. With the weather as it has been this year, there is likely still a 2-3 week window for overseeding the lawn with fairly good success. It might be a good idea to overseed now and then do another overseeding in the fall to thicken it up. Also, for weed control, it would help to use mesotrione (tenacity) at seeding. There is a starter fertilizer that contains the tenacity to help with start-up of the turf and to keep the weeds down while establishment occurs. It would just help to get some type of cover crop or turf down to reduce the amount of bare soil that weeds can grow into.
3. This caller has henbit. Would it be controlled well with the Tenacity? If so, should he use a stronger dose of the Tenacity because he has tried it with limited success?
A. It is Never a good practice to use pesticides at a higher rate than what is listed on the label. A lot of research went into finding the correct rate for best control of a pest. Henbit is hard to control this time of year, it is best controlled in the fall. It will die as soon as the heat of the summer comes on because it is a winter annual and doesn’t live well in hot weather. Treat in the later fall, October, with a 2,4-D product for best control.
That caller also has a peach tree that just flowered for the first time. It has two 2-inch long cracks on the tree trunk, each on opposite sides. What can be done with this?
A. Unfortunately this tree is not going to live long. There is nothing to do to fix the tree once cracks like this happen. This large of an opening is very damaging to the tree and will not allow the tree to live long. If it is out in the open where it won’t damage anything if it falls, leave it until it dies.
4. A caller has been trying to get a native grass prairie started for a few years now with limited success. He has a mix with Blue Grama, buffalograss, and little bluestem. What can he do to get it to grow better?
A. Don’t give up yet. Be sure to control the weeds with herbicides, 2,4-D won’t harm the grasses but will manage the weeds. After some photos, it shows that there is still some grass in there, but it is very early for these warm-season grasses. Keep mowing to keep the seed heads down for the weeds.
5. Can potatoes still be planted yet this spring?
A. Yes, get the potatoes in soon, and they should be fine yet this year.
What do you do for Pampas grass with a dead center?
A. Dig it up and divide it and replant it. This can still be done this spring.
She has a crabapple that has dead branches in it, can those be cut off now or should they be removed in the fruit tree pruning window of February-March?
A. Remove dead branches anytime of the year that they appear.
6. A caller wants to know when to spray for bagworms?
A. It 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.
He also wondered when and how to fertilize trees?
A. It really isn’t necessary to fertilize trees in Nebraska. They can get the nutrients they need from the soil naturally.
How do you water trees that were recently planted?
A. water them one time per week with a slow trickle from the hose for about 20 minutes each time they are watered.
When is the best time to prune cedar trees to shape them?
A. Most anytime would be fine with a cedar tree, but the best time is in the late winter to early spring.
7. This caller has Austrian pines that are turning brown on the tips of the branches with short needles. What is causing this and how can it be controlled?
A. This sounds like tip blight. It can be treated now with a copper fungicide. A second application should be made 7-14 days after the first application.
8. What is the best thing to mulch asparagus with?
A. Grass clippings, straw, hay, or wood chip mulch can all be used to mulch asparagus. It would be best to hand pull weeds and then use preen that is labeled for use in asparagus before applying the mulch. If there is a problem with brome grass, use roundup carefully around the asparagus first as well. To carefully get the glyphosate on the brome and not on the asparagus either paint it on with a foam paint brush or 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.
9. A caller has been trying to start seedlings of spruce and fir trees for a few years with limited success. He thinks it may be due to root rot because when he pulls them up the roots look rotten. How can he get the trees to grow?
A. After discussion, it seems that he doesn’t overwater the trees and may in fact not be watering them enough. He also said that he can get the trees to grow in another, more neglected, location. It was suggested that he do a soil test to see what is going on with the soil in this desired location. It might be that there is a hard pan underneath these trees that is impeding water movement through the soil causing the roots to rot.
10. This caller has been trying to get grass started and is having difficulties. He has used an aerator, seeder, lawn roller, and then waters the seed well and it is not coming in very good.
A. It seems his practices are good, so he may try a soil sample to see what the nutrient and pH levels are in his soil.
11. The last caller of the day wanted to know what the difference is between a Sycamore and a London Plane tree?
A. These trees are 2 different species of very similar trees.
This is the Q&A for the Yard and Garden show for July 27, 2018. 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 3, 2018. 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 caller of the day has tomatoes that are rotten on the bottom. What is wrong with them and what can be done?
A. This is blossom end rot, it is where the blossom end (or the end of the tomato farthest from the plant) rots. It is due to a calcium deficiency due to uneven watering. The calcium is in the soil, but uneven watering makes it unavailable to the plant. Mulch will help keep the soil at a uniform moisture level to help protect plants from this disorder. Blossom end rot is a short-term problem in our vegetable crops. It tends to only affect the plant for a the first couple of harvests of the year and then the plant grows out of it. You can cut the black end off of the fruit and eat the rest.
2. When is the best time to prune lilacs? This caller has one that is a large, overgrown lilac that needs to be pruned.
A. The best time to prune a lilac is in the spring within a couple of weeks after blooming has concluded for the season. If it is a very large, old plant, it can be pruned all the way back to 6-8 inches above ground in a rejuvenation pruning. Rejuvenation pruning does just what the name says, rejuvenates an old, less productive plant to provide better foliage, flowering, and overall health. Rejuvenation pruning can be done in the fall. The lilac will not flower for a couple of years following this type of pruning, but it will bloom again.
3. This caller planted a large amount of black walnuts last year. Now the weeds are taking over the trees. How can the weeds be controlled without injuring the trees?
A. Simazine is a pre-emergent herbicide that can be used around walnut trees that have been established for at least 12 months. This is a pre-emergent herbicide so it won’t clean up the weeds that are growing now. For those weeds, it would be best to do hand weeding with a hoe to not injure the roots of the trees and then apply the Simazine this fall. Be sure to follow the label on how to apply and how to mix the chemical.
4. A caller has a redbud tree that is 15 feet tall and is now developing a split where multiple leaders have forked up from the main trunk. What can be done to prevent further splitting? Can one side of the tree be removed to fix the split?
A. The best option would be to remove one side of the tree or bolt it together. However, removal of one side of the split would result in removing too much of the canopy of the tree. Either side of the split would be pruning off a branch that is more than 1/2 the size of the trunk, which is not recommended. Because this is a redbud, and it shouldn’t get much larger than it is now, bolting the 2 sides together may be an effective management option for this tree. A bolt in a larger tree in this situation would likely not be very effective once the tree grew to full size, but with a smaller tree it would be more beneficial. The best thing for all trees is to remember to prune them while they are young to prevent these situations from occurring, but that is not always an option and it is hard to remember to do this.
5. This caller has some pin oaks that were planted 2 years ago and are 2-4 feet tall. The new leaves are being eaten off the tree. The leaf veins are still on the tree, but most of the rest of the leaf is gone. He has looked and can’t seem to find any caterpillars. What would cause this and how can it be managed?
A. This is likely due to scarlet oak sawfly. It is a common pest of oak trees that has 2 generations per season here and we are just finishing up the second generation in the immature stage. Because the damage is mostly finished for the year and because the tree faced minimal damage, there is no need to spray for this sawfly.
6. A caller had a daylily plant that she transplanted a month ago and it died. What caused that? What time of year is best to transplant peonies?
A. June and July are not the time of year to transplant anything, it is too hot, humid and dry to move a plant. I would assume the daylily died due to heat stress. When a plant is moved, it takes time to build the roots back up to where they can survive such heat and low water that we see in the summer months. It is best to wait to tranplant anything until the spring or fall of the year so they can become established in cooler temperatures than in the heat. Peonies can be transplanted this fall, in September. Remember to keep the plant at the same depth in the soil or it will not bloom.
7. The last caller of the day sent some photos of his red maple trees wanting to know if they will survive?
A. The trees were planted last year and now one of them has no leaves on the top 1/2 of the canopy of the tree. The other has very wilted leaves. When the top half of a tree dies like this, it is likely due to a watering or root issue. I would say this tree should be replaced, it will not grow out of it. The roots could have been injured in the nursery or at the garden center he purchased the trees at. The roots also could have been injured when they were planted. The tree that is still fully leafed out may have a chance to live, give it TLC and it might pull through. Water the tree with 1 inch of water per week and add a mulch ring around the tree that is 2-3 inches deep. The leaves could be wilted due to heat and drought stress and the watering and mulch will help it to survive.
This is the Q&A for the Yard and Garden show for June 22, 2018. 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 3, 2018. 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: Kathleen Cue, Dodge County Extension Educator
1. The first caller of the day has cauliflower that is turning purple in the garden. What is causing this and can it still be eaten?
A. This is a response to the heat. For next year, blanche the heads just after they begin to form by tying the large leaves up around the cauliflower heads to protect them from the sun or purchase self-blanching varieties. This cauliflower can still be eaten even though it has turned purple.
2. When is the best time to move asparagus?
A. Spring would be the best time for planting asparagus. It is more beneficial to just start a new asparagus patch rather than transplanting. It would be difficult to get all of the plant and there are a lot of newer varieties that will do better with heat and other conditions. If you transplant what you already have growing, it is still best to wait 3 years before heavy harvest again, so it would be beneficial to start over since this asparagus bed is already 20 years old.
3. A caller has nutsedge in their lawn, how can it be controlled? Roundup didn’t seem to work for it.
A. Roundup would not be effective in this situation because roundup is for grass control, while nutsedge is a sedge. For best control of nutsedge, it is best to use either Sedgehammer or Tenacity. Both of these chemicals should be effective, but they should be applied prior to the first day of summer to reduce the population for next year. Also, nutsedge tends to grow in areas of the lawn where the soil is compacted or water tends to sit, reduce the compaction and get the turf growing better to control the sedge better.
4. This caller has a few walnut trees that the tops look good, but near the base of the trunk the tree is losing bark. He recently added some soil and river rock around the trees. Will the trees survive?
A. When adding soil and rock around a tree that had been planted for a while, it changed the grade around the trees. This can lead to many problems with the tree because it makes the tree too deep in the soil, especially after the roots were at a higher level in the soil for multiple years. This will lead to the death of these trees. The bark could be coming off because of the death beginning in the tree or it could be due to possible damage to the roots when the soil and rock was moved in. Either way, the trees will die. Enjoy them until they do or until they become a hazard to homes, cars, or people found underneath them.
5. What would be a good replacement tree for scotch and Austrian pines?
A. Diversity is a good thing to remember when planting a new trees. Diversity includes species and age of trees. This caller has a great deal of trees to replace in a CRP, it is advised to not replace all of these trees at the same time so they have a diversity of age as well. Good choices include Douglas fir, concolor fir, hemlock, eastern red cedar, blue spruce, black hills spruce, Norway spruce, and Ponderosa pines.
6. A caller has a windbreak with bagworms. Is it too late to spray this year? What should he spray with?
A. We should be ok in the window to spray for bagworms. It is best to spray after the bagworms have germinated for the year until when the bags have developed over 1 inch in length. Once the bags are larger than 1 inch long, the chemicals will not be very effective. Tempo or Bt products would be the best choices for control of bagworms, but most any general insecticide will work.
7. This caller has a 20-year-old red maple that only has leaves on the west side to cover only 1/4 of the tree. What is wrong with the tree?
A. When that much of the tree has died back, it will not recover. It should be removed to reduce the hazards that will appear from a dead tree.
8. A caller has a newly planted blue spruce. How long should they maintain watering the tree? Should it continue through the winter months?
A. Newly planted trees should be watered throughout the growing season, and even during the winter. If we don’t have a lot of snow cover through the winter months, it is important to water an evergreen tree about once a month on a warmer day. When watering in the winter, water in the early to mid-day to allow all of the water to soak into the soil rather than freeze up on top. It would be best to continue watering this tree at least for 3-5 years on a regular basis. However, even a 30-year-old tree needs to be watered some in years of drought. It would be best to always continue to water this tree, even if only sporadically.
9. This caller wondered if adding drain tiles when adding a raised bed around an established tree would help it to survive with this practice that is not recommended?
A. Adding a raised bed to an existing tree is not an issue with drainage. Adding more soil to where a tree is already living can decrease the amount of oxygen that the roots are able to get which can then kill the tree. Also, adding this soil make it so that the trunk of the tree is underground which can decay the trunk and lead to crown rot or other bad conditions that also lead to death of the tree.
10. A caller has a pin oak that the roots are starting to pop out of the soil around it. What can be done for it?
A. Wood-chip mulch can be used to cover up the roots as they show up out of the soil. Do not add soil or increase the soil level. Avoid rock mulch as it can be too hot for the plant. Adding a mulch over the roots will prevent you from mowing over the roots and injuring them. Plants can be planted among the roots as well, but don’t add soil to do that.
11. Is it too late to prune lilacs?
A. Lilacs will begin producing flower buds for next spring shortly after they finish flowering this year. They should be pruned within a couple of weeks after blooming has finished in the spring. They can be pruned this late, but it will reduce the flower production for next year.
12. This caller has lilacs that have never been pruned for many years. How, when, and how much can she prune now?
A. A rejuvenation pruning may be beneficial for this situation. Older lilacs, if never pruned, have unproductive wood. This will lead to less leaf production, less flowering, and often much of the leaf and flower production will be just at the top 1/3 of the plant. When this happens, it is best to just prune the lilac off 6-8 inches above the ground to allow it to regrow with younger, more productive wood to produce more leaves and flowers throughout the whole plant. Rejuvenation pruning should be done just after flowering or in the fall for best health of the plant.
13. The last caller of the day wants to know about planting and growing blueberries and currants in Nebraska. He has pots he wants to plant them in to plant the pot into the ground. Is that necessary? What type of soil should be used?
A. Blueberries are not the best option for Nebraska soils. They must live in highly acidic soils, which we do not have. If determined to grow blueberries in Nebraska, it is best to grow them in a pot in the ground that can be brought up every year to amend the soil with acidic fertilizer or peat moss. Serviceberries may be a better choice to blueberries for Nebraska. Serviceberry is a native plant so it will grow in our natural soils with a lot less care and they have more antioxidants than blueberries do. There are also some newer varieties that have berries larger than blueberries. Currants will grow just fine in our natural soils and need no ammendments.
This is the Q&A for the Yard and Garden show for June 15, 2018. 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 3, 2018. 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 UNL Extension
1.The first caller of the show wants to know how to attract more fireflies to his yard?
A. Fireflies like moist environments. So a location of higher shade that is kept moist with dense plantings will attract them to your landscape. Also, just keeping the lawn watered will help.
2. This year has high populations of ticks found in nature. Many ticks around this area have been identified by Jim Kalisch as being the Lonestar tick. Is this species of tick increasing in population in Nebraska?
A. Lonestar tick nymphs are being found often now. They have been found in the southeast portion of Nebraska. The range for this tick has spread north over the past decade or 2 to include the southeast corner of Nebraska. Prior to this, the Lonestar tick was found further south of Nebraska. This tick is significant for health reasons because it spreads many diseases including Southern Tick Associated Rash Illness (STARI), rabbit fever and erlichiosis. It also can causes a food allergy to red meat. Because of this, it is always good to remember to use insect repellent sprays and check yourself for ticks when coming inside from outdoor activities.
3. A caller has a blue spruce that was planted from a container last spring at 3.5 feet tall. Now it is turning brown on top and the branches are getting a shepherd’s crook at the end of the branches. What is causing this and can the tree be saved?
A. This is likely a fungal disease called sirococcus shoot blight. The best time to spray the trees is in May with additional sprays every 3-4 weeks as rain occurs. It is a little late for the spraying of this tree, but it would still be beneficial to spray the tree to reduce the spread. Using a liquid copper fungicide would be best. Next spring, spray the trees when the shoots are 1/2 to 2 inches in length.
4. An email question came through asking how to get rid of pumpkin bugs in the garden this year, he faces them every year?
A. From his description, these are likely squash bugs. They are common pests in pumpkins, as well as in cucumbers, squash, zucchini, and melons. If these bugs are in pumpkins that are for ornamental use only, not for consumption, a systemic insecticide called acetamiprid can be used. Be careful if using in a garden with other edible garden plants, read the label for the PHI to tell you how long to wait from when you apply this product until you can harvest again. If these plants will be used for consumption, eight or bifenthrin would work for less PHI. Still pay attention to the PHI for harvest times.
5. This caller has oriental poppies in her garden that have faded now. They are planted in an area that is becoming overtaken by weeds. She would like to plant mums around the poppies to get a longer season of interest. How can she work the soil to plant the mums and kill the weeds, while not harming the poppies.
A. Tilling through the garden space may not be the best answer. If you till through weeds, it can sometimes cause more of a problem. Many weeds will propagate vegetatively, so new plants will form from each of the cut pieces of the main plants. Also, it would be difficult to till around poppies safely. I would recommend carefully using glyphosate on the weeds for better control, do not use any 2,4-D or Dicamba products this time of year due to problems with these chemicals turning into gas and moving to non-target plants. Spot spraying the weeds or painting the chemical on the leaves would get more of a kill for the weeds and the glyphosate product will not turn into a gas and it deactivates as it hits the soil. Finally, just go in and just dig holes where the new mums will be planted.
6. A caller wants to know when the best time is to move tiger eye sumac?
A. Fall would be fine to move this sumac, such as in September.
This caller also has a 5-year-old peach tree that has borers. How can the borers be controlled?
A. For borer control, it is best to treat the base of the tree and the branch junctions with bifenthrin. This chemical will have to be reapplied a few times through the growing season to help with the lesser peach tree borer and the peach tree borer which emerge at different times of the year. Applications should be made in June and again in July and August for best control.
7. This caller has a 2-year-old black raspberry. The new growth is curling and turning black, it seems to be moving from the tip of the leaf inward. What would cause this?
A. This could be from a scorch issue. Make sure that the plants are getting enough water, but check before just watering more. Often when we get scorch we automatically go to overwatering which can also be quite detrimental to the plant. For more information on scorch and how to deal with it, visit the Gro Big Red Blog Post on Scorch from Kathleen Cue.
8. A caller emailed pictures of his fir trees that are having some issues. One, was planted about 6 years ago and the bottom few branches have turned brown. He watered through the winter but has not yet this spring. The other fir was replanted about 4 years ago and the top is green, but the bottom half is sparse. What can be done for these trees?
A. The bottom branches of this tree could be just dying from shade or from a needle drop issue. That branch or 2 can be removed and the tree should be fine. It would be best to water this tree. Put the sprinkler in the root zone of this tree weekly for an hour or so to help it. As for the smaller tree, it is not going to make it. The lower portion is quite bare and it will be very difficult for the tree to come back from that.
9. What do you do about sandburs in a lawn?
A. Crabgrass preemergent herbicides should be used earlier in the season to control sandburs before they grow. Sandburs are a summer annual weed just like crabgrass. For post-emergent control, quinclorac products will work best. If it is in a driveway or other non-plant area, roundup 365 might be fairly effective.
10. A caller has a birch tree that needs a large branch removed, when is the best time for this? They also have a pear tree that needs some pruning, when is the time to do this? And when can they prune a mock orange bush?
A. New research is showing the timing for pruning has changed from what was previously recommended. We now recommend pruning in the late spring to early summer, so that would be right now for both the birch and the pear tree. It is better to wait until a little later in the spring to prune birch trees to avoid problems with heavy sap flow. The concern with this is that it was stated that a large limb needed to be removed, which can be quite harmful to the tree. Don’t remove a limb that is more than 1/2 the diameter of the trunk and do not remove more than 1/4 of the tree in one growing season. Removing a large limb leaves a large wound that the tree is not able to seal up. If the wound doesn’t get sealed, then decay can begin to move through the tree which can lead to the death of the tree in many years. In addition, removing more than 1/4 of the canopy in one season will remove a great deal of the photosynthetic area from the tree, which can harm the growth and development of the tree. The mock orange bush should be pruned within a few weeks after blooming for the year because it is a spring blooming shrub.
11. The last caller of the day wanted to know about pruning tomatoes and how to do it?
A. Tomatoes can be pruned if desired, but it is not necessary. If desired, only prune on indeterminate tomatoes, avoid pruning determinate tomatoes. Determinate tomatoes already will only grow to a certain size and produce a certain amount of tomatoes so they do not need to be pruned. Pruning tomatoes can decrease the amount of tomatoes produced and increase the size of the tomatoes and it can help increase air flow to reduce diseases. It will also help keep your tomatoes off the ground. When the plants are young, remove some of the branches. In some locations, 2 or more leaves will start to develop from one node, remove all but one. For more information on pruning tomatoes, here is a guide from Minnesota Extension.