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.
You don’t have to be a die-hard gardener to keep a great looking community of plans around your house. Many homeowners find a manicured and weed-free lawn to be just as pretty as any rose garden. When you’re maintaining a sea of grass, every plant that isn’t yours must be eradicated. Control of deadnettle is just one such task that turf keepers face year after year. It sounds tricky, but don’t fear! We’ve got some deadnettle weed management pointers to help you with this formidable foe.
Growing a thick, healthy lawn is the first line of defense against these mint cousins, since the grass will easily out compete 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.
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 long.
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.
Henbit may look similar to purple deadnettle, but there are some key ID traits to look for to tell these weeds apart.
I’ve received a few questions asking what the purple weed is that is appearing in the landscape. It is probably either purple deadnettle (Lamium purpureum) or henbit (Lamium amplexicaule).
These weeds often get confused because they look similar. They both belong to the mint family, have square stems, have an ascending growth habit, opposite leaves, purple/pink flowers, and are winter annuals. When trying to identify if you have purple deadnettle or henbit, key ID traits to tell them apart are listed below.
Key ID traits for henbit:
Key ID traits for purple deadnettle:
Purple deadneetle that was found in Van Buren County this spring (2016).
Photo taken by Nancy Carr
Since both are winter annual, preventing seed production is key to management. Tillage and herbicides are effective management options for these weeds. Both species are flowering now and management with herbicides will not likely result in full control. Fall or early spring herbicide applications will be most effective at managing problem infestations. Contact your local Iowa State University Extension & Outreach field agronomist for resources regarding control of these weeds.
Another weed that belongs to the mint family and is making lawns appear purple right now is ground ivy (Creeping Charlie, Glechoma hederacea). Unlike henbit and purple deadnettle that are winter annuals, ground ivy is a perennial weed, and also generally stays confined to lawns.
Unlike some of the other examples on this list, Ambrosia artemisiifolia does not have a taproot, so weeding is easy: just pull it up. Ragweed thrives in poor soil, so keeping your lawn healthy and well-fed will also discourage ragweed.
There are two types of ragweed, but the form that haunts lawns is Ambrosia artemisiifolia, common ragweed.
Common Ragweed (Ambrosia artemisiifolia)
Or, you can eat your dandelions. Yes, dandelions are edible and delicious. All parts of the plant are good in salads or as cooked greens.
If you choose to engage the enemy organically (by digging it up), you will have to be persistent, too. The tiniest pieces of vegetation in the soil will regenerate.
Purslane (Portulaca oleracea)
Unlike many lawn weeds, this one is indigenous to North America, not a foreign invader.