Q: We have what the neighborhood nurseries call "creeping Charlie" growing all over our lawn. We've tried pulling it out, digging it up, reseeding, overseeding, cutting the grass short, and leaving the grass long. Nothing seems to work. Help!
—Steve and Jan Christiansen, Palatine, Ill.
A: Roger Cook replies: Creeping Charlie, also called ground ivy or gill-over-the-ground, is a perennial and a highly invasive evergreen weed of the mint family. It loves conditions that grass doesn't: shade, and soil that's wet, acidic, or compacted. So if you see this weed, it's a message that your lawn needs help.
Chemical weed killers might get rid of it, but unless you change the conditions that encourage this pest, it'll just come right back. Get a soil test and add the nutrients or minerals that are missing. Prune or remove adjacent trees to admit more light. Reduce sources of excess water, such as runoff; don't overwater the grass; and run a core aerator over it in the fall to reduce compaction. After aerating, spread a mixture of compost and sand over the grass so that the soil will drain better. If you reseed a somewhat shady area, use a grass blend suitable for shade. And if you still have problems after all that, give up on grass and plant a noninvasive groundcover that's more to your liking.