Gardening Q&A

Q:Is there a way to eliminate crab grass without killing other grass?

Answer: There are some post-emergent crabgrass killers that will kill crabgrass and not your fescue. However, they are most effective early in the summer when the crabgrass is still immature. Even back in early September, it was probably better to ignore it, knowing it will die with the first frost. You can aerate your soil and plant new fescue seed right over the existing crabgrass. By the time frost kills the crabgrass your new seedlings should be up and growing.

For next year, the best control is with a pre-emergent applied in early March. If there is a lot of crabgrass this year, or you have a lot of it in the yards around you, you may want to make a second application of pre-emergent in early June.

Q:I just purchased a weeping willow tree and notice that it has some little worms on it. Many of the leaves have been eaten completely. What are these things? Also, what could I apply to the tree that would take care of these pests without hurting the tree?

Answer: There are several worms that can feed on weeping willow leaves. There are several systemic insecticides available now so you can treat the ground around the plant, rather than having to spray the whole tree. The chemical will be picked up by the roots and moved up into the leaves. That way it affects only the insects that are feeding on the tree.

By now, though, I'm sure they are gone and there's no need to treat. However, if the worms return next summer, you could take a few to your local office of Virginia Cooperative Extension and get them identified. Once you know what they are, the people at the Extension Office can help you can plan your treatment.

Q:We had three honey locusts cut down this summer. All summer we were plagued with sprouts coming back off of their roots. Not only in my yard but in neighboring yards as well. Even when the weather was dry last summer, they kept coming back as fast as I could cut them down. I used several stump removers and brush killers on the stumps, but the sprouts kept coming back. Do you have any other suggestions?

Answer: Sprouts are common with locust roots. The roots don't realize you cut down the tree because you didn't want it. They just know they need to produce some leaves to absorb sunlight and make food. If they don't send up sprouts to produce leaves they will eventually starve to death. The sprouts will stop now for winter. If they return in the spring, you should leave the leaves on the sprouts when you spray them with the herbicide. Most herbicides like this are taken in by the leaves and translocated to the roots. Glyphosate also has a stump treatment rate that is used by painting it on the stumps. However, it has to be done immediately after cutting the tops off. That way the cambium is still open and receptive to the herbicide.

Q:I planted grass seed Labor Day weekend and the grass is up and looking good. However, I've noticed some tiny round leaf weeds coming up throughout the lawn. What are they and what can I do about them?

Answer: I can't say for sure what they are without seeing them. However, chickweed and henbit are two of the most common winter annual weeds to infest our fescue lawns. Their seeds were dropped last spring and they laid dormant all summer in your soil. The cooler weather of fall stimulated them to germinate and the things you did to get your grass growing helped them along.

The good news is they will be easy to kill this fall and you can treat them after you have mowed your new grass three times. Normally by the end of October, you can safely use a selective herbicide that will kill these broadleaf weeds and not hurt your fescue. If you don't treat them this fall, they will mature through the winter and compete with your grass early next spring. By that time, they will be dropping seeds for next year's crop.

Richard Nunnally is a freelance writer and host of WCVE's monthly gardening show, "Virginia Home Grown." He can be contacted at .