What is Purple Deadnettle?
Purple deadnettle (Lamium purpureum) is a common annual weed that belongs to the mint family, which explains why it’s such a pest. Like other mints, purple deadnettle is an aggressive grower that spreads like wildfire anywhere it can get a foothold. You’ll recognize it and its cousin, henbit, by their distinctive square stems that hold up an umbrella of tiny flowers and small, pointed leaves reaching up to an inch (2.5 cm.) long.
Deadnettle Control
Getting rid of deadnettle weeds is much more challenging than dealing with many other annual weeds because they tend to go to seed before mowing season even begins. Couple that with the thousands of seeds each plant can release persisting in the soil for years, and you’ve got one durable weed on your hands. One or two purple deadnettle weeds popping up in the lawn can easily be plucked by hand and disposed of as soon as they appear, but a larger population requires a more complicated solution. Growing a thick, healthy lawn is the first line of defense against these mint cousins since the grass will easily outcompete the weeds for nutrients and growing space. Consider planting a grass more compatible with the growing conditions if you’ve got a spot in the yard that’s plagued with these plants. Sometimes, the thick shade a tree casts or a low spot that catches water can make it difficult for the grass that lives on the rest of your flat, sunny lawn to grow– this is when you need a special grass blend. Check with your local nursery for grass seed better suited to these rough conditions. Post-emergence herbicides that contain metsulfuron or trifloxysulfuron-sodium can be used against purple deadnettle erupting in Bermuda grass or zoysia grass, but pre-emergence herbicides are much safer for other grasses. Be sure to apply pre-emergence herbicides in the late fall or early winter, before the purple deadnettle starts to germinate.
