This is the Q&A for the Yard and Garden show for May 13, 2016. 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 5, 2016. 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: Fred Baxendale, Horticulture Entomology Specialist, UNL
1. The first caller of the day wanted to know when to transplant Peonies? She also wanted to know if she moved them away from the black walnut tree would that help them grow?
A. It is best to transplant peonies in the fall, but it can be done in the spring as well. It would be fine to move them in the spring as well. It would be beneficial for the plant to be moved away from the black walnut tree to get away from the toxicity produced by the tree as a form of natural weed control for the tree to other plants. Black walnuts produce Juglone which reduces growth and, in some cases, kills the other plants so the black walnuts have less competition for water and nutrients. Planting things 50 yards from the tree will get it out of the zone where damage can occur.
2. A caller has a rose that is old and has grown to 6 feet tall. When can he transplant it? Also, what are the red “ticks” he found around his gardens when he has been working in them recently?
A. Roses are hard to transplant. Do the transplanting in the early spring of the year and take as much of the rootball as can be dug up when it is moved to help the shrub overcome the transplant shock. Maintain adequate water once it is moved. The red “ticks” would be clover mites. These are not damaging to the plants but can leave red marks on house siding and if inside on the walls and curtains. You can treat these with permethrin or insecticidal soap.
3. This caller has Peonies that accidentally got cut back drastically this year. Will they live through this and should she do anything for them?
A. They should be fine but they probably won’t bloom this year. Make sure they are adequately watered and they will regrow by the end of fall. They should be fine again next year.
Signs of an Emerald Ash Borer Infestation from Boulder Colorado
4. A caller has 2 ash trees in her yard. She has heard about Emerald Ash Borer and wanted to know if there was anything she could do to protect her trees?
A. Emerald Ash Borer (EAB) has not been found in Nebraska and we recommend waiting until EAB has been found within 15 miles of your trees before you begin treating them. It takes 2-4 years for the damage to show up in our trees once it is here, so you will have time to treat them when it does get here. In the meantime, don’t move firewood here from other locations and increase the diversity in your landscape to help fill in holes that may appear when EAB takes out your ash trees. Also, watch your trees for signs of EAB including top dieback, suckering at the base of the tree, increased woodpecker damage, bark falling off, and D-shaped exit holes and alert Nebraska Extension if your trees exhibit any of these signs of damage.
5. This caller has a 10-year-old red maple that has struggled to leaf out the past couple of years. The middle of the tree is entirely void of leaves. Should he remove the center of the tree?
A. Removing the center will not fix the problem. This could be a root issue or it may have been improperly planted which would take around 10 years to show signs of damage. This tree is near the end of its life and removal of the entire tree should be contemplated. There could be borers in the tree but that would be a secondary issue and using an insecticide on them wouldn’t fix the whole problem with this tree.
6. This caller planted a Bradford Pear 2 years ago, it is leaning now. What can be done to correct the leaning?
A. Don’t stake the tree to try to pull it back to the correct position. When we stake a tree to try to pull it back upright, this can cause a girdling issue to the tree and it is very damaging to the tree. Because this tree has only been planted for 2 years, it would be a good idea to try to dig it up and reposition it.
7. A caller has steep hills around his yard and doesn’t want to have to mow it. What groundcover choices would he have to grow instead of grass?
A. Buffalograss, dwarf sumac, crown vetch, or potentilla would all be good choices for this type of growing environment.
8. A caller wanted to know if she could use vinegar for weed control in the flower garden?
A. It is best to use pesticides that are labeled for use in the garden. Pesticides for weed control have been rigorously researched to ensure that they work properly and cause limited harm to the environment if applied correctly. When we use non-gardening products in the garden, there isn’t always research to know how those products will work in the garden and it may cause more problems to our plants or it may cause problems if they get into stormwater. If you want to avoid pesticides, it would be better to use cultural and mechanical methods of weed control such as hand pulling and using mulch for weed control.
9. This lady has ant hills in her lawn, what can she use to control them?
A. Ant colonies would be spreading now. Leave them alone now, but if they start to overrun the lawn or come inside, you can spray them with permethrin or bifenthrin. If they are not taking over the lawn, they are a predator insect so if you don’t need to control them, they can be beneficial for other bad insect management.
10. This caller has a barberry that she wants removed. Should she call Diggers Hotline before digging it up? Also, how can she remove and kill daylilies growing in her landscape?
A. Always call Diggers Hotline before you do any type of digging. It is a free service that will help you before a problem occurs. As for the Daylilies, the best option is to dig them up. Using pesticides on them would need repeated applications over many years. When you dig them up, you can offer them to your friends and family.
11. How can you control bromegrass in flowers and in strawberries?
A. In the flower garden, you can spray a Grass-B-Gon product to control the grass and not harm the flowers. Do not spray this to where it hits your lawn or any ornamental grasses. As for the strawberries, this product is not labeled for use in strawberries or other edible crops, so mulching and hand pulling would be the best option. You can also paint Glyphosate (Roundup) products on the leaves of the grass among the strawberries and not harm the strawberries.
Crane Fly photo by David Cappaert, Bugwood.org
12. What are the giant mosquitoes this caller has been seeing flying around? What do they do? Are they mosquito killers?
A. These would be crane flies. They are not harmful to us. They feed on nectar when they are adults, but can sometimes be a problem in the turf. They are not mosquito killers, they are in the same order as mosquitoes and look like a large mosquito, but do not eat them. The immatures live in moist environments.
13. Would it be ok to spray a 2,4-D product this weekend?
A. Yes, 2,4-D can turn into a gas and spread to non-target plants if the temperatures for 72 hours after spraying is above 80 degrees Fahrenheit. So, with this cool down predicted where the temperatures will be in the 60’s for the weekend, this would be a great time to spray. Just make sure that the wind speeds are very low.
14. This caller has onions that the tops are dying back on. They tops curl up and die, why is that?
A. Onion thrips can cause streaking on leaves, this may be from onion thrips. Onion maggots will feed on developing bulbs as well. It could also be from a root rot issue. Dig up one of the onions that are not looking healthy and inspect the bulb for signs of insects or disease.
15. A caller has a recently planted black oak tree that has all of the leaves stripped off of it.
A. It could be from canker worms. They are a short-lived problem in our oak trees. Using the Eight product will help to control them.
16. This caller transplanted walking/winter onions. The bulbs are developing below ground and on top they are flowering but not developing the bulbs on top of the plant. What would cause that?
A. Try to fertilize the plant to help it with nutrients that may be missing from the growth of the plant.