This is the Q&A for the Yard and Garden show for April 15, 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: Jeff Culbertson, UNL Landscape Services
1. The first caller of the day has asparagus that she planted last Spring. What needs to be done with the plant now?
A. Light harvest can be done the second growing season and then full harvesting can begin the third season. Mulch it now to keep weeds down, herbicide sprays are not able to be safely used too close to growing asparagus. Cut the plants back in the fall after they have grown well all season. Fertilizer can be applied now or in the fall.
2. How do you control moles in the lawn? How do you control grubs in the lawn?
A. For mole control, see this guide from the Internet Center for Wildlife Damage Management: http://icwdm.org/handbook/mammals/mam_d51.pdf Make sure that you have found an active run area before implementing any traps by stomping the mounds down for a couple of days prior to setting the trap. For grub control, the best option is to apply a product containing Imidacloprid around the third week of June.
3. This caller from the Southern part of the United States said that it is difficult to grow asparagus in the south. Is this due to the lack of dormancy in the south compared to what we have in Nebraska?
A. Yes, asparagus would need to have a rest period that occurs during our winter in Nebraska. However, the roots are also prone to root rot problems, so it might be that your soil could be too high of clay that isn’t allowing the asparagus roots to dry out enough.
4. Another caller has Iris that they have sprayed with Sevin for iris borers that are always a problem. Is this the best product and when should she be applying it? Also, she applied lime to the plants and now they are a lime green color instead of the deep green they are supposed to be. What is causing this discoloration?
A. Lime is used for acidic soils to raise the pH. In Nebraska, most of our soils are heavy clay and therefore already have a high pH. The addition of the lime to the soils in this case is causing chlorosis on these iris plants. It will work through over time, but for a couple of years the iris may look a little tired. The Iris borers have not shown up yet, but a treatment with an imidacloprid, permethrin, or bifenthrin soon or just as the larvae come out would be ideal for control.
5. This caller is wondering what the timing is for fertilizer with crabgrass pre-emergent herbicide? He is also wondering how to control bindweed in bromegrass?
A. Anytime in the next week or 2 would be ideal for fertilizer and crabgrass pre-emergent use this year. The soil temperatures are at 54.9 degrees Fahrenheit for the 7 day average. Crabgrass will germinate at temperatures between 55-60 degrees Fahrenheit, so you can begin applying your control methods anytime now until the end of the month for best control. The bindweed can be controlled with trimec if used 2-3 times per summer. Keep the bindweed mowed to prevent flowering from occurring to reduce the amount of seed left in the grass.
6. A caller has cedar trees that were recently pruned from the bottom up. What would be a good grass to grow under these trees?
A. A fescue grass would grow well in this shady environment. Also, a nice groundcover such as purple leaf wintercreeper would be a good alternative to grass to reduce mowing under the tree and to grow better in the shade of the tree.
7. This caller from Hickman has a cherry tree. Every year they mow off many “little trees” that grow up and around the cherry tree. Is there anything else to do to reduce the occurrence of these trees?
A. Suckering occurs with many different tree species. These suckers may be growing off of the roots of the main tree so chemicals should not be used or else you may end up killing the desired tree as well. Cutting them off or mowing over them before they grow too large would be the best options for control.
8. This caller has fruit trees. He is wondering if a product called “fruit tree drench” for insects would be ok?
A. Not knowing the active ingredients in this product makes it hard to answer the question. Systemic insecticides are not usually safe for use in plants that are edible because a systemic insecticide will move throughout the entire plant, including into the edible parts. It is suggested to do more research on the safety of the product or to move to a spray type of insecticide that is not systemic to reduce the health hazards that may be a problem with systemic insecticides.
9. Another caller has an apple tree that is 7-8 years old. The last 3 years it has produced nice apples but they are rotten inside. Now there are not many apples that are not rotten on the inside. What can be done for this?
A. Sanitation is going to be key for controlling this disease, known as black rot of apples. A orchard fruit tree spray program can be used to minimize the damage as well. Pruning may need to be done to remove any branches that are dead or diseased.
10. A caller wanted to start a new strawberry patch. How far should the plants be spaced in the garden and what should be done to the soil for improvements?
A. Till in compost and topsoil for increased organic matter and reducing compaction in the soil. Space the plants 1 foot apart.
11. This caller has a maple tree that is not budding out and has not yet lost the leaves from last spring. Will it survive?
A. Some maples, such as the sugar maples, have not yet leafed out for this spring. Use the fingernail test to scratch the bark lightly on smaller branches to see if there is green underneath the bark. Green under the bark means the tree is still alive and waiting to come out of winter dormancy, brown under the bark means it died over the winter.
12. A caller wants to know about the “spray on grass”. Will it work for overseeding?
A. Should work ok, but check with the types of grass seed included in these cans. Many of these mixes have perennial rye which doesn’t last long in Nebraska environments. Also, check for the amount of weed seed found in the mixture.
13. Is it too late to thin Iris plants?
A. The best time to transplant and divide iris plants is in the fall. Use a garden fork to lift them from the ground. Look for borer holes, and then replant them making sure to not plant them too deeply.
14. What is the best advice for improving soils for growing watermelons?
A. Lighter soils are best for growing watermelons. Add compost to improve the fertility.
15. A gentleman has cherry trees, apricot trees, and peach trees. What type of mulch should be applied to help keep the trees watered?
A. Organic mulches should be used, such as the wood chips. They need to be applied at a uniform depth of 2-3 inches in a ring around the trees that is at least 2-3 feet wide around the tree. Water the trees for about 45 minutes every 10-14 days, more may be necessary during the hot, dry periods of the summer. Use a soil probe or long screwdriver to see if the trees need water. Push the probe into the soil up to 12-18 inches deep, if there is resistance any time while pushing into the ground, the trees need water.
Grape Hyacinth photo from Ricky Layson, Ricky Layson Photography, Bugwood.org via Creative Commons License.
16. A caller has grape hyacinth growing in her lawn. What can be done for management?
A. Mow it off. This is a short lived annual plant that is close to the end of its lifetime for this year. There is no need to use chemicals to control this plant.