This is the Q&A for the Yard and Garden show for May 8, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.
Guest Host: No guest host due to COVID-19 and social distancing
1. The first caller of the show has shrubs that bloomed this spring, when can they be pruned?
A. Any shrub that blooms in the spring should be pruned within about 3 weeks following the spring bloom period. This would include plants like lilac, forsythia, and the spring blooming spireas.
2. A caller heard me discussing the need to cover tender annuals for the next few nights with the cold temperatures predicted. Do those need to be uncovered during the day or can the cover just stay on for the next few days? Does she need to cover her wisteria or strawberries that are just beginning to bloom?
A. The plants that should be covered are annuals and tender perennials, this includes the warm season crops that have already been planted in your garden this year. You can cover them with a sheet, a row cover, or a bucket. They should only be covered at night. In the morning, when the temperatures warm up above 40 degrees, the coverings should be removed to allow the plants to receive sunlight. Perennials, including wisteria, should be fine. Strawberries that have blossoms set would push new flowers and fruit later but if you don’t want to lose this first crop, you may put a row cover or sheet over the plants to protect the developing fruits.
3. This caller has a flowering tree that is suckering in the lawn. How can they control the suckers without harming the tree?
A. If these are growing in the yard, they can just be mowed over and will eventually die but not harm the tree. You can also cut the suckers off individually, if desired. Don’t treat these with any herbicides like roundup because it can go into the main tree and kill that as well. While some products, such as Sucker Stop are available, these will only slow sucker growth; not stop it. Some trees and shrubs are more prone to suckering. For example, crabapples, purple leafed plums and lilac.
4. A caller has 3 acres of bare area to manage. What is the best or cheapest options for him regarding grass or some other type of covering?
A. Native grass or pollinator or wildlife mixes would be a great option for this type of location. You can purchase seed at many locations including Anderson Seed from Odell or Stock Seed Farms from Murdock.
5. This caller has black spots on her grass that have recently showed up. She wasn’t sure the type of grass but most likely it was Kentucky bluegrass.
A. It is hard to tell for sure what the problem is from the description given. I asked for a photo to be emailed to know for sure.
6. A caller has cedars that have developed odd orange structures on the branches. What is that and how can it be controlled?
A. These are the galls of cedar-apple rust. This disease needs 2 hosts to complete its lifecycle. The galls are hard, gray/brown structures on the cedar trees over the winter. In the spring, when it rains, these galls open up to allow the spores to move to the apple trees. When the galls open up they are orange structures that resemble an octopus due to all the telial horns around the gall. The disease causes no problems to the cedar trees, but will cause lesions on the leaves and fruits of apple trees. If you have a susceptible apple tree, now is the time to spray with a fungicide to prevent the disease from affecting your tree. For more information, view this NebGuide.
7. This caller has asparagus growing. This is the 4th or 5th year of growth. He has fertilized often but not this spring. He did use a weed and feed on the asparagus, but asparagus wasn’t listed on the label. Why is his asparagus growing so spindly?
A. As we harvest, eventually the spears will start to get spindly which means that is the time to quit harvesting for the year. However, the weed and feed product may have some negative consequences on this plant. He didn’t know what exactly the product was that he used but he said it didn’t have asparagus listed on the label. In this case, the product should NOT be used on the asparagus. Make sure to always read and follow the label on pesticides and only use it on plants listed on the label.
8. A caller has planted potatoes a couple of different times this year, but they continue to not sprout. What would be the problem?
A. The weather has been fairly cool, and especially cold overnight. The plants are just waiting for more desirable weather before growing. Give them a little more time and they should grow as long as a disease doesn’t set in or they rot in the ground.
9. If volunteer redbuds have come up throughout a landscape, can they still be moved to a more desired location this year or is it too late?
A. Yes, they can still be moved now. As long as they are moved prior to the hot, dry environment of late June through July and August, they should be fine.
10. What is the best way to manage weeds around asparagus?
A. Mulch is the best option to keep weeds down around asparagus. You can use the preen that has asparagus listed on the label to control annual weeds. Otherwise hand-pulling will help keep them down as well. At the last harvest of the season cut down all the spears, so there’s no foliage or anything above the ground. Rake the soil over the top of the spears. Then spray the plants with glyphosate (RoundUp). Glyphosate becomes bound by the soil particles when it hits them, so will not damage the crowns below ground. This will control annuals and tough perennial weeds. The spears will then re-emerge from the soil and not be damaged by the glyphosate at all. Apply some mulch to help with the weed control, then Preen.
11. This caller gets little brown spots on the leaves of her cucumber plants every year. This often will kill her plants over time. Is there anything she can do to control this so her plants will survive longer?
A. Using mulch and watering at the base of the plants with soaker hoses will help. Overhead irrigation, such as with sprinklers, can splash disease spores from the soil to the leaves of our plants or from leaf to leaf or plant to plant. Watering from below helps reduce the spores splashing. Mulch also helps to keep the separation from the soil where the spores are. Fungicides, such as a copper fungicide, could also be used if desired. Make sure that cucumbers are listed on the product and follow the PHI (Pre-Harvest Interval) for length of days to wait from application to harvest.
12. A caller has spiny vines growing up the trees in her windbreak. How can she kill the vines and not harm the trees?
A. You can go through and cut off the vines and follow that up with a stump treatment using either 2,4-D or a glyphosate product, such as Roundup. Use the concentrate and just paint it on to the freshly cut stump for best control. Do NOT use Tordon, that will likely kill the spruce trees, and it is against label directions. When cutting the vines off at the base, they will stay in the tree but they will die because they have no roots. Treating the base of the plants will kill the roots to eliminate the problem with regrowth.
13. This caller has a patch of asparagus is not doing well this year. He recently piled logs nearby the patch. Would those logs be causing a problem with the growth of the asparagus? The logs are about 3 feet from the asparagus.
A. The logs shouldn’t be causing a problem from that distance, there isn’t black walnut in the wood piled there. It may just be that the asparagus needs to be fertilized. A general fertilizer can be applied in the spring to help with growth. If the spears are getting spindly now, harvesting should be discontinued. The plant will tell you when to quit harvesting based on the size of spears.
14. A caller has cucumbers, zucchini, and potatoes that have just emerged their first leaves. Should those be covered this weekend with the cold weather that is predicted? Would peonies need to be covered?
A. Yes, those warm season crops that have very tender new growth should be covered for the next few evenings. Remember to uncover them during the day. The peonies should be fine, but a freeze could damage the developing flower buds depending on how cold it gets, how long it stays that cold, and how far developed the buds are.
15. This caller asked how to spray her apple trees to prevent problems with insect and disease problems.
A. Orchard fruit tree sprays will combat both insect and disease problems on fruit trees. Sprays should begin as soon as pink is seen in the buds, but should cease during blooming. Since this caller hasn’t begun spraying yet, it would be fine to just start as the blossoms are falling off the tree. You want to allow the pollinators to come to the tree without harming them, so no sprays should be done while the trees are blooming. This spray should be applied every 10-14 days through the growing season, up until harvest.
16. The final caller of the show has a concolor fir that the needles on the bottom third of the tree have turned brown. What is causing this problem?
A. It was hard to determine the problem with this fir over the air. I asked for follow-up photos to help diagnose the problem.