This is the Q&A for the Yard and Garden show for July 17, 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: Sarah Browning, Lancaster County Extension Educator
1. The first question of the show was from a listener who brought green beetles into the studio for identification. These were found in his trees and he wants to know what they are and how they should be controlled?
A. The beetles were Green June Bugs. These are a native insect species that can be found on many different plants. They can be ravenous feeders in grapes and occasional feeders in vegetable gardens, but on trees they are not very damaging. If they feed on vegetable gardens or grapes, you can use sevin or eight on them.
2. This caller has a Linden tree that is 12 years old that is losing leaves now. The leaves turn brown as well. They did recently give it a deep watering, but that isn’t seeming to help. What is wrong with the tree?
A. Check the tree thoroughly for Japanese Beetles, it is one of their favorite plants to feed on. They will feed heavily causing the leaves to look like lace and then the leaves will turn brown. The trees can look fully brown by late summer. If it is, you would want to work with an arborist to spray the tree. Be very careful with what you spray lindens with and when you spray them to not harm pollinators. If the leaves don’t have holes in them, it could be from a stem girdling root which cannot really be fixed so late in life.
3. A caller has peppers that have white spots on them. What caused this?
A. This is likely due to drift from Roundup or another glyphosate product. Wind can drift the particles which will leave white, irregularly shaped spots randomly across the leaves. If it was from a disease it would be more tan or brown in color.
4. This caller has tomato plants that are loaded with green tomatoes that are not turning red. What is disrupting the maturation process of the vegetables?
A. When the temperatures are so hot, as they have been, the fruit ripening process is slowed down or stopped completely. They will mature when the temperatures break to cooler temperatures.
5. A caller wants to know when she can harvest wild flower seeds to reseed in a new area in her landscape?
A. The seed needs to fully mature while still on the parent plant. Make sure the seed head is dried and brown, then you can cut off the stalk and move the seed to the new location. If you can easily shred the seed head with your fingers, the seed is mature and can be reseeded in a new location.
6. This caller has tomatoes and beans with troubles in the garden. The tomatoes have brown leaves on the bottom of the plant, what is causing that? The beans have flowers on them but no fruit has been set, why are they not producing beans for harvest?
A. The tomatoes likely have early blight, it is a common fungal disease that we are seeing this year. You can just remove the infected leaves and discard them to reduce the disease. If the plants still have troubles, you can spray them with a copper fungicide if necessary.
As for the beans, the heat is likely delaying fruit set. In temperatures this hot, the flowers can develop but the pollen can be killed so fruit will not set. Give the plants a little more time and they will start producing beans once the temperatures cool off.
7. A caller has columbines that are in a garden bed overrun by weeds. She wants to redo the bed to help get rid of the weeds. When is the best time to dig them up and do some work then replant them?
A. The fall or spring would be a good time to dig up, divide, move, and redo the garden space. When the temperatures are cooler. When we move or divide plants we break their root system, making it harder for the plants to get the needed moisture to survive. It is best to do these things when it is cooler so the drought stress isn’t as high.
8. This caller has tiger lillies that were knocked over by the wind and broken. Can the seed be moved to another location?
A. Make sure that the seed matures on the plant. If the stems were broken so the plant is not still maintaining the seed, they may not be able to be reseeded to a new location because the seed wouldn’t be mature. If that is the case, you can divide the plants and plant some in the new location. September would be a good time to do this.
9. Is there any post-emergence herbicide that can be used in an asparagus patch that won’t hurt the asparagus?
A. No, there isn’t anything for post-emergence. You can use preen that is labeled for use in the asparagus in the spring prior to germination of the annual weed seed and again in the middle of the summer. This will help with annual weeds. For perennial weeds you can use roundup or another glyphosate product early in the spring prior to emergence of the asparagus. You can also use it after the final harvest of the year. Cut out all of the stems of asparagus and pull mulch or the soil up over the stems so no green is showing, then spray the roundup over the bed to kill the weeds and not harm the asparagus.
10. This caller has an old lilac that has leaves that look bad. Can it be cut down now?
A. It can be cut back with a rejuvenation cutting in September. This is when the lilac is cut back to 6-8 inches above ground. This will help to rejuvenate the plant to newer, healthier growth. This method will disrupt the flowering for a year or two, but it will eventually flower again. The lilac can also be caned out every year by removing 1/3 of the largest, least productive canes every year to remove those canes that are not improving the health of the plant.
11. A caller asked why his tomatoes look good but have no fruits or flowers at this point? It was hit by herbicide drift a month ago, but they have grown out of that.
A. The heat is pushing back maturation of the fruits right now. However, if your plants have no fruits at all, the herbicide injury could have stunted the plants. The combination is pushing back maturation of the fruits. Eventually they will flower and produce fruits, just give it time.
12. The last caller of the day asked about green beans that are blooming but have no fruits. What is causing this?
A. The heat is likely delaying fruit set. In temperatures this hot, the flowers can develop but the pollen can be killed so fruit will not set. Give the plants a little more time and they will start producing beans once the temperatures cool off.
*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.