Yard and Garden: July 26, 2019

Yard & Garden blog, 2019

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

1. The first question of the show was about catalpa trees. They were pruned in the past, but now they have a bunch of smaller branches growing out of the location where the branch was removed from the tree.

A. The branch that was removed was likely not correctly done. If the cut wounded into the trunk of the tree or left a stump, it would cause the tree to push a lot of new growth like suckering. Make sure that proper pruning cuts are followed and that you don’t leave a stump. Follow these steps when pruning a tree to ensure it is removed correctly with minimal damage and avoid the branch-bark collar to avoid a flush cut which will not heal correctly.

3-step pruning cut
Proper pruning cut, University of Missouri Extension

2. How do you control clover in the lawn?

A. Clover can be found in an under-fertilized lawn. It may be a good practice to fertilize at least one time a year to help the lawn compete with the clover. If treating with chemicals, the fall is the best time of year to treat for broadleaf perennials such as clover, dandelions, and creeping Charlie. Apply a 2,4-D product or one containing triclopyr twice in the fall. Mid-September and again in mid-October is best. Other IPM strategies for controlling clover include mowing high and aeration if necessary.

Co Potato Beetle Pupa 2
Colorado Potato Beetle Pupa

3. A question came in via email about orange things on potatoes. There are tiny orange bugs found on potato plants in her garden. What are they and how can they be controlled?

A. These are Colorado potato beetle larvae. Pull any off that are found and smash them or spray with sevin to control them as they emerge as beetles.

4. A caller has creeping Charlie in their yard. When is the best time to spray for that?

A. When using chemicals, the fall is the best time of year to treat for broadleaf perennials such as clover, dandelions, and creeping Charlie. Apply a 2,4-D product or a product containing triclopyr twice in the fall. Mid-September and again in mid-October is best. Other IPM strategies for controlling creeping Charlie include mowing high and aeration if necessary.

5. This caller has cucumber plants with a lot of flowers but no fruits. Why are these plants not producing fruits?

A. You should check the flowers to see if they are all male flowers or if there are female flowers as well. Male flowers just have a skinny stalk behind the flower. Female flowers have a tiny cucumber behind the flower. If male flowers are all that are present, give it time for the plant to produce female flowers. If both male and female flowers are present, there could be a problem with pollinators. Avoid spraying while bees are active, attract bees with other pollinator plants, put up a bee house to bring bees in. If you are using row covers, be sure to uncover the plants for a while during the day so bees can pollinate the plants.

6. A caller called in with a good suggestion to help with cucumber plants. He grows his on a trellis so they can get better airflow and less diseases. It also makes it easier to harvest the plants this way.

7. This caller has a small hackberry that is 12-14 feet tall with 3 trunks growing together. There are small splits all along the trunk like some type of injury, what caused this and will his tree be ok?

A. These could be spots from hail injury, even from a few years ago. There is nothing to do for hail damage. Most trees will come through just fine. If the damage is intense, the tree could have more problems.

8. Is it too late to trim lilac bushes?

A. Yes, it is too late for general pruning of lilacs. They should be pruned within the first couple of weeks following the flowering period. If a rejuvenation pruning is desired, the fall would be a good time to do that, wait until late September to mid-October for that.

9. A caller who manages a golf course has a couple of Linden trees that were under water for about 2 months this year. They sat in a flooded area of the golf course for this time in the spring. They originally did leaf out but since then the leaves have turned brown. Will the tree be ok?

A. There is likely no life left in these trees. Lindens are not adapted to have their roots that wet for that long. The trees probably had enough energy left in the roots to push out leaves but now have ran out of energy. It would be best to remove those trees and replace them with something more adapted to sitting in water from time-to-time, such as bald cypress trees.

10. The final question of the day was sent via email. This listener has a gravel driveway that is partially sloped. How can they keep the weeds out of this driveway and not harm the grass at the end of the slope?

A. Roundup 365 would be the best option for this. It contains glyphosate as well as imazapic which lasts longer than the glyphosate alone. On the label it states to only apply once a year and to “spray until THOROUGHLY WET”, so for best results spray to this extent. Soil sterilants aren’t recommended because they often run off into adjacent plant material such as grass and kills it. Always read and follow the label when using pesticides.

*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.

 

Yard and Garden: June 28, 2019

Yard & Garden blog, 2019

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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Bindweed

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

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

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

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

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

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

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

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

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

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

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

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

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Rust on a Pear tree

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

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

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

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

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

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

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

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

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

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

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

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

 

 

Yard and Garden: June 30, 2017

Yard & Garden for blog, 2017

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

Guest Host: Connie Fisk, Cass County Extension Educator

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

1.The first caller of the day wanted to know if he could fertilize his tomatoes, potatoes, and cucumbers with the same fertilizer?

A. Yes, the same product could be used for all three of these crops. Be careful when fertilizing to not use too much Nitrogen during the bloom period which will cause the plants to grow large but not produce any fruits. Also, too high of Nitrogen for the plants can lead them to grow large and dense which can lead to more fungal diseases.

2. A question came through email asking what would cause red spots on strawberry leaves?

A. This could be either due to leaf scorch or leaf blight. The leaf scorch will have red spots that have a red or purple center and the leaf blight will be a red spot with a gray center. For both of these diseases, you can use Captan fungicide.

strawberry leaf diseases comparisons

3. How soon can peonies be cut off?

A. Peony leaves should be left on the plant through the growing season and can be removed in the fall when the leaves turn yellow. Otherwise, this time of the year you should only remove the flower stalks. Leaving the leaves on the plant will help the plant build sugars to help it bloom early next year.

4. A caller planted Karl Forester Reed Grass in 2 locations in his landscape at the same time this spring. One location, the grasses are doing well, but in the other location, the grasses are much smaller and not growing well. The worse plants are on the east side of the house while the good grasses are on the west side of the house. What would cause them to grow so differently?

A. The east side of the house would be in more shade than those plants growing on the west side. Most of our grasses like to be grown in full sun, this difference in sunlight could cause the difference in growth. Because they are in different locations, a nutrient deficiency could be causing the few on the east side to be growing less. Add a general fertilizer to help with growth.

5. This caller is applying a fertilizer with 24% Nitrogen every 7 days to her tomato plants. Is this too high of a percentage of Nitrogen for the plants to grow well?

A. The percentage isn’t as important as how much is applied. Applying a fertilizer every 7 days is too often. For most vegetable gardens, fertilizing three times a year will be sufficient. With this high of Nitrogen in the soil the plants will not produce and may grow too large and develop diseases in the deep canopy.

6. A caller had golf ball sized hail a couple of weeks ago that hit his tomato plants. The plants are still growing and have leaves on them. Will they be ok?

A. Yes, they should be fine. Keep them mulched to help reduce competition with weeds and keep them uniformly watered as needed. Don’t fertilize the tomatoes because they are stressed from the storm damage and fertilizing a stressed plant will increase the stress.

7. This caller wondered if grass clippings will negatively affect the soil in his vegetable garden? He had been using the grass clippings for a couple of years and now his vegetable plants don’t look as healthy as before he started using grass clippings.

A. After discussions, the caller said he had been using herbicides on his lawn and using the grass clippings on his garden. Pesticides can have a long residual on the grass clippings and this can negatively affect the plants. Especially if he was using broadleaf herbicides such as 2,4-D for dandelions. Broadleaf herbicides will damage vegetable plants which are all broadleaf plants. It would be best to avoid using his grass clippings if he is to continue using herbicides on his lawn. He can use other types of mulch such as straw, woodchips, newspaper, cardboard, or grass clippings from a neighbor who isn’t using herbicides on his or her lawn.

8. A caller has hollyhocks that have copper colored, round spots on the leaves and the leaves are falling off. What is the problem and what can be done to improve the flowers?

A. This is likely due to hollyhock rust, a common fungus of hollyhocks. Remove the leaves as they develop the disease and destroy the leaves and plant parts removed in the fall cleanup. Fungicides can be used if necessary, such as a liquid copper fungicide.

9. Do weeds need to be controlled in sweet corn or will the plants grow tall enough and shade them out soon?

A. Weeds should always be removed to reduce competition and lead to better overall plant growth. You can hoe the weeds out and use mulch between rows.

10. This caller has squash plants growing in black containers that are growing in potting soil. They are not thriving, what could be the problem?

A. The pot could be getting too hot because it is black. It would be beneficial to add mulch around the container or paint it another color to keep the roots cooler inside. It also could be drought stressed. Plants grown in a container get drought stressed sooner and need to be watered more than those growing in the ground because they have more limited root space. It also might be beneficial to add a general fertilizer to help the plants grow better.

2015-04-15 11.03.06
Kabatina Tip Blight

11. A caller has flagging on cedars that is causing the tips of the branches to turn brown. What would cause this damage to 20 year old cedars?

A. This could be due to bagworms which would be very small yet. Bagworms can be sprayed with any general insecticide. It also could be due to drought stress or Kabatina tip blight. There is no fungicide control for Kabatina. The best management is to cut out the affected areas.

12. This caller has sweet corn growing in his garden. The corn is about 2 feet tall and is now tasseling and it is very light colored. What would cause this problem? He is watering his garden for 1.5-2 hours every night.

A. This is likely due to overwatering. Vegetable gardens need about 1 inch of water per week, watering every night is not necessary and that much water would cause the nutrients to leach down through the soil, which would account for the lighter green coloration. The corn will likely not produce this year since it is already tasseling.

13. A caller wondered if the wood chips being produced from all of the downed trees would be safe to use as mulch around living plants or if there would be an issue with insects in the mulch?

A. This would make a good mulch for your plants. If there was an insect in the trees being chipped, the chipping process will kill it.

14. This caller has grapes that were hit by herbicide drift this spring. The leaves were all the size of a nickel and deformed, but the plants are not pushing new growth. What should they do to help the grape plants make it through this stress? Should they fertilize the plants?

A. Unfortunately, grapes are very sensitive to herbicide drift. 2,4-D can drift about 1/2 miles and Dicamba can drift about 1 mile, so it can move from a long way and grapes will be the first to know. If these are mature plants and they are pushing new growth, they should be fine. Don’t fertilize the plants, this will add more stress to the situation. Keep them well watered to help them through.

15. A maple tree was recently hit by hail. Now the trunk and branches have wounds on them. Should anything be done to cover these wounds?

A. No, don’t apply anything to the tree or cover the wounds with anything. Allow the tree to go through it’s normal processes to seal up the damage to reduce decay further into the trees.

16. A caller has cantaloupe plants that are not growing well. They have very small leaves but they are flowering already. What can be done to help them grow better? They are growing in a garden with many other vegetable crops that are growing much better.

A. Remove the flowers that are developing on such a small plant. When plants try to push flower growth and fruiting, they reduce their growth. Removing the flowers will push the plants to try to grow more before they begin flowering.

17. This caller is growing strawberries that have been growing for a few years. They bloomed and looked healthy this year, but the strawberries produced were very small. What would cause this problem? Also, what will help stop strawberries from rotting if they ripen on the ground?

A. The plants should be thinned at the end of the year to help increase the size of the berries. They also could be dealing with an issue of poor pollination. The cool, wet weather this spring led to low pollination because the bees don’t like to fly in the rain. Poor pollination may lead to development of the fruits, but at a much lower size than normal. Poor pollination can also cause the plant to drop small fruits from the plant before they mature. Mulch the strawberry beds with straw to help keep the berries from laying on the soil and rotting as they mature.

18. A caller from the Geneva area has an ash tree. Should he be treating for Emerald Ash Borer now?

A. No, Emerald Ash Borer (EAB) has only been found in Greenwood and Omaha in Nebraska and we recommend waiting until the beetle has been found within 15 miles of your tree before beginning treatments to reduce injury to the trees and to reduce the amount of insecticides in the environment. There is no need to treat for a problem that we don’t have yet.

19. This caller has one apple tree and needs to get a second tree for pollination. What would be a good variety?

A. It is necessary to plant a second variety of apple tree to help increase pollination. Look at the local nurseries to find good choices that go with the variety you already have planted. They will have a chart to show which trees pollinate which.

20. A caller has a fungus in the lawn every year. This fungus shows up in different locations throughout the yard every year and she treats with a fungicide every year. Is there anything she can do to make it so she can stop treating every year?

A. If you see the fungus in your lawn every year, you would need to treat for it earlier in the year before the fungus appears. If the fungus is present before treatments begin, they will not stop the damage that is already present.

*A caller later on the show suggested that these spots may be due to a dog urinating in the lawn, which can cause brown spots similar to many of our summer fungal diseases. There is no way to stop the brown spots left after a dog urinates on it, you would need to walk the dog somewhere else to do his or her business.

21. The final caller of the day has tomatoes that are growing well and they are now 3.5 feet tall, however, they have no blossoms on the plant. What would cause this?

A. This would be due to high Nitrogen levels in the soil. It cannot be fixed at this time, but don’t add any additional fertilizer to the garden for a couple of years to bring the level back down.

Storm Damage to Trees

2017-06-15 19.43.56

This time of year, storms tend to sneak up on us, as we saw last Friday night. Unfortunately, some of those storms can be severe and cause damage to us, our homes, our vehicles, and even our trees. When storms bring strong winds, hail, and tornadoes, these things can all do different kinds of damage to our trees. Cleanup doesn’t end with the branches on the ground.

2017-06-20 09.26.08

If heavy winds come and break branches, those breaks need to be cleaned up to a good pruning cut to allow the plant to seal up the wound. If the storm broke the top out of the tree, it would be a good idea to get a Certified Arborist in to look at the damage to determine if the tree can be salvaged. Allow the Arborist to do the pruning because there are methods that can be done to start a new leader in the tree to help it fill back in and continue to grow upward.

2017-06-20 09.26.52

In addition to branches breaking, some of these trees may have even had bark ripped all the way down the trunk of the tree. When trees have open wounds that are large, it takes a long time for the tree to seal up that location, if it can ever be done. This is a great location for insects and diseases to come into the trees and cause secondary effects on the trees. Unfortunately, there is nothing that can be done to “fix” this type of wound. It is best to just leave it alone and let it heal on its own. You can remove excess bark that is hanging off the tree, but don’t paint or wrap the wound with anything, this can hinder the sealing process of the tree.

Hail can cause damage to the leaves and bark of our trees. If your trees leaves look ragged and ripped due to hail, it is mostly aesthetic damage. The leaves are still on the tree and able to produce sugars through photosynthesis for the trees so it isn’t as damaging as it looks. Damage to the bark on the trunk and on the branches can be more problematic, unfortunately there is nothing that can fix this but time. You will always have round-to-oval shaped wounds where hail hit the tree, but over time the tree will seal these wounds and it won’t be too problematic. If there are a lot of large hail wounds to a small tree, it might be the demise, but give it time to see if it pulls through. For a second opinion have a Certified Arborist look at the tree.

Some trees were uprooted in these high winds. According to John Fech, Kathleen Cue, and Graham Herbst from Douglas-Sarpy County Extension, the younger the tree is, the more chance it has to survive storm damage that caused it to lean. If the tree is 0-5 years old, it has a good chance to survive leaning and should be staked as soon as possible, as long as it is not closely located to people or property. If the tree is 5-10 years old and is leaning, there is a 50 percent chance that the tree will survive. Consult a certified arborist to determine the survivability of that tree, as the degree of lean is what will cause the tree to live or die. If the tree is more than 10 years old and is leaning, it becomes a hazardous tree. If that tree is in an area where it is in close proximity to people or properties, it should definitely be removed. However, if this tree is on an acreage or farmstead and is further away from people or property, it may be able to survive in that location, but a certified arborist should still be consulted to know for sure.