Gardening columnist Tim Daly answers the following questions from readers:
Question: My bermudagrass lawn has many weeds. Many of them will die off as the weather gets colder, but then another crop appears during the winter. How can I keep these weeds under control where they do not harm my lawn’s appearance? – Joe, Duluth
Answer: Joe, for the weeds that are currently a problem in your lawn, you need to apply a post-emergent herbicide, such as the Bayer Advanced, Ortho, or Spectracide products. They will control existing weeds. To reduce the winter annual weeds, such as annual bluegrass, chickweed, and henbit, apply a pre-emergent herbicide during September. These chemicals control the weeds as they germinate. Use again in March to prevent the summer weeds. Several brands are available for purchase. Many are granular and usually require an application of water. Please follow all label directions and safety precautions when using pesticides.
Q: I have planted my fall vegetable garden with a variety of plants. Recently, some cabbage, broccoli, and collards have a small green caterpillar chewing on them. What can I apply that will control them and not be toxic? – Anne, Snellville
A: Anne, what you observe are cabbage worms and cabbage loopers, caterpillar pests that trouble these types of vegetables. One of the best control is the use of material that contain the bacteria Bt. It targets certain caterpillar pests but does not harm anything else if applied according to label directions. The insecticide is sold under the trade names Dipel and Thuricide. You can purchase them at local garden centers. These materials are quite useful in controlling these pests.
Q: In my backyard, I see multiple yellow jackets going in and out of a hole. From experience, they are quite aggressive and inflict painful stings. How can I control these insects without getting stung by them? – Louise, Buford
A: Louise, yellow jackets tend to be problematic in the late summer and fall. Recently I had an unpleasant encounter where I received multiple stings. These insects build their nests in the ground. Search the area to find the entrance hole to their nest, which you have already found, fortunately. Get some flying insect aerosol spray. Stand back several feet away from the next and direct the spray stream to the hole. Apply it later in the day when they are not as active. This method will kill the yellow jackets in the nest. Some will be returning to it, so be careful. Wait a couple of hours before entering the area to ensure all of them have gone.
UGA Extension Gwinnett will be having the following virtual educational programs for homeowners:
• Sept. 15: 6 to 7 p.m. — Fall is for Planting https://zoom.us/j/96276788537
• Sept. 22: 6 to 7 p.m. — Gardening with Herbs https://zoom.us/j/98447261009