More Wascally Winter Weeds! Henbit, Purple Deadnettle, and ChickweedBy Toni Leland (tonileland)
April 26, 2010
Henbit & Purple Deadnettle
Henbit (Lamium amplexicaule) and Purple Deadnettle (Lamium purpureum) are members of the mint family (Lamiaceae) and are hard to distinguish from each other. They both grow like weeds (pun intended) and can take over a garden in one season. They are both easy to hand pull, but difficult to identify when they first emerge.
Square stem on both plants is distinctive.
Purple Deadnettle grows upright.
Henbit spreads quickly in the grass.
Tubular purple flowers of Henbit.
Both Henbit and Purple Deadnettle have distinctive greenish-purple square stems (see photo at far left). The seedlings for these two varieties look alike: the cotyledons have a white tip and a notch at the base of the leaf where the petiole connects. As the plant matures, the leaves of Purple Deadnettle show prominent veins, an almost crinkly appearance; at the base of the stem, the leaves are round and hairy. The leaves of Henbit are circular and only have a little veining. Henbit looks similar to ground ivy (or creeping charlie), but is more upright.
Both plants have purple leaves at the tip of each stem; Purple Deadnettle’s leaves are triangular, while Henbit’s leaves surround the stem and are attached directly the stem without a leaf stalk. Flowering time for both plants is between March/April through October/November. Purple Deadnettle has groupings of 3 to 6 purple flowers at the top of the stem; Henbit’s tubular flowers can be pink or purple and are more sparse.
From an agricultural standpoint, these two plants have significant consequence in soybean fields. They are both strong hosts to the Soybean Cyst Nematode, and heavy infestations tend to occur in crop fields where these weeds have been allowed to grow.
Control in the home landscape is a matter of preference. Pre-emergent products should be applied in the fall after these annual weeds have gone to seed. Hand-pulling and mulching is the best method for eradication in controlled landscape beds. Regular mowing through the season will control these weeds in turf grass.
Chickweed is a member of the Pink Family (Caryophyllaceae) and comes in two flavors: perennial and annual (see photos below). Mouse-ear chickweed (Cerastium vulgare or C. fontanum) is perennial and grows low to the ground, creeping through the turf grass and covering large areas quickly. Common chickweed (Stellaria media) is the annual version of this weed and grows absolutely anywhere! Chickweed is on the invasive plant list of the USDA Forest Service.
Mouse-ear chickweed immigrated to North America from Europe, where it quickly naturalized as a result of its adaptation to various habitats: disturbed soil, sandy shores, moist woods, dry waste areas, damp ground, lovely flower beds, and lush lawns. It is not drought tolerant, but can remain green under the snow. The plant reproduces through seed and rooting of stem nodes.
The seedlings of this variety are hairy and the stems are sticky; the stems are prostrate and grow from 6 inches to 2 feet long. The opposite leaves are smooth-edged with a pointed tip, and covered with hairs on the upper surface and lower veins. The flowers are tiny and white, and bloom at the end of the stem from April/May through October.
The annual, Common chickweed, has small, smooth, elliptical light green leaves with pointed tips. The stems are creeping and the plant has shallow roots, making it easy to hoe or hand-pull; however, any root pieces left behind will produce new plants. Flowers are small, star-shaped, with five petals.
This plant loves cool, moist areas, and spreads by seed, dispersing from 600 to 15,000 per plant. Control in the garden landscape is best done by cultivation and hand-pulling, although in large areas of turf grass, chemical control may be required. Check state and label requirements; it is resistant to some herbicides.
Mouse-ear chickweed is hairy and sticky.
Common chickweed flower.
Common chickweed patch in turf grass.
Common chickweed single plant.
 "Identification of Six Alternative Winter Annual Weed Hosts for Soybean Cyst Nematode". Valerie A. Mock and Bill Johnson, Pest & Crop, Issue 25, 10/12/07, Purdue Cooperative Extension Service.
Chickweed flower photos from Wikipedia Commons; remaining photos by Toni Leland ©2010