Purple deadnettle good & bad


Q. What is this terrible, purple weed? I fight it every spring?

Susan from Canfield

A. Not only is it your garden, but it is everywhere. Have you seen the farmers’ fields as you drive by, with these clouds of purple, short flowers? It is actually quite beautiful to see, but frustrating to deal with in the garden or field. Its dense foliage and quick growth keep soil temperatures cooler in the spring, delaying planting and holding moisture.

This is purple deadnettle (Lamium purpureum), not to be confused with stinging nettles or common nettles. There are a couple of differences in this early spring flower. First, deadnettle is a member of the mint family, with a square stem. Secondly, though it may have hair, it does not have the stinging tricomes for the stinging nettles. There is another similar garden weed (or plant depending on your view) called henbit (Lamium amplexicaule), which also blooms purple in early spring.

The top of the plant, leaves and all, develop a purple tinge. This nettle is a winter annual. That means it emerges as a developing whorl in the fall. It lies dormant over winter, then in the spring (early March through April) develops a head 6 inches high with purple/pink flowers. Many of us think it appears out of nowhere, but the tiny seedling has been visible all winter.

While a problem weed, this plant is a perfect host for the emerging early spring bees, pollinating flies, moths and butterflies. The early mats of dense foliage and flowers grows on disturbed soil. The plants spread through seeds and rhizomes. The relative, henbit, has rounder leaves. The nettle leaves are scalloped with a pointed tip – like a spade. Though it can grow up to 16 inches, it seldom reaches more than 6 inches. The flowers are two-lipped with a tubular shape similar to a snapdragon. After flowering, the plant dies back to the ground.

If you want to actually plant some deadnettle, choose a damp shady site. I take seed heads from those around the yard and spread them in barren areas that will not be mowed. This plant has herbal connotations and is used in teas and home remedies. It is a valuable natural wildflower to our Ohio pollinators.

If you want to control it, it’s easy. Keep disturbed areas mulched with at least 1 inch of mulch. Watch for winter annuals as they emerge and form tiny rosettes in August through October. Control them when they are small.

For pictures and other information, go to: http://go.osu.edu/deadnettle.

Stephanie Hughes is an OSU Extension master gardener volunteer in Mahoning County. Call the office plant and pest clinic at 330-533-5538 to submit your questions. Regular clinic hours are 9 a.m. to noon Mondays and Thursdays.

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