Purple dead nettle, a winter annual weed.
This spring, we have a couple of first class examples of winter weeds in our landscapes. Chickweed has crept into lawns and flower beds along with purple dead nettle.
Winter annual weeds germinate in fall or winter, surviving cold weather to mature the following spring as the temperatures rise.
A lot of the blame goes to last year’s drought. The drought kept many homeowners from applying late season herbicides to control winter weeds because the lawn was not actively growing or in poor condition. The drought prompted homeowners to skip an application of fertilizer late in the season.
Weeds are opportunistic — give them an in and they’ll take it.
A lawn’s open spaces and weakened conditions provide a perfect place for common chickweed (Stellaria media) to form large, dense mats in the lawn and garden, choking out healthy turf. Common chickweed is a low growing, shallow rooted weed with small, slightly oval leaves that usually are a paler green than the lawn. Mouse ear chickweed has a similar growing habit but its leaves are slightly hairy. Each sports clusters of white flowers.
Purple dead nettle (Lamium purpureum) also can be found in the lawn, but more likely in the rich soil of flower and vegetable beds. This upright weed with purple flowers gets about a foot tall. It resembles the ornamental lamium many gardeners use as a ground cover. The triangular leaves have a reddish or purple color at the top.
In flower and vegetable beds, hand pull chickweed and dead nettle. A thick, healthy lawn fends off weeds better than a weak thin one. Corn gluten is an effective, natural pre-emergent that keeps weed seeds from sprouting. This product works well in lawns and vegetable and flower beds.
For more information about winter weeds, visit the University of Minnesota Extension’s Weed Control in Lawns and other Turf.
I’ve got plenty of Purple dead nettle in my lawn and flower beds, too. I figure the best defense is to keep it from setting seed.