Common Lambsquarters is a broadleaf summer-annual weed that can be found anyplace the soil has been disturbed. The growth habits of the common lambsquarters vary with its location. If growing along the road or in an open field, it may reach three or four feet in height. Yet those plants found in lawns may produce seeds when only a couple of inches tall. Lambsquarters prefer rich soil and are often found in vegetable gardens.
The first two true leaves that appear are opposite and ovate with smooth edges. Later leaves are alternate, arrowhead-shaped and with unevenly-toothed edges. At the top of the plant, the leaves become long and narrow. All of the leaves are pale green and covered with white, mealy granules that give the appearance of frost. Stems are erect and often have light-green or red lines.
Flowers are small, inconspicuous, yellow-green, and occur in clusters at the tips of branches and upper leaf axils. These flowers occur from July to September. Black seeds are contained in an utricle by a thin papery covering.
ControlThe best methods of weed control in the home vegetable garden are mulching, handpulling, rototilling, hoeing and preventing the weeds from going to seed. Because of its short, branched taproot, lambsquarters can be easily hand-pulled from moist soil.
Prevention by use of good cultural habits should be the first line of defense in eliminating broadleaf weeds such as lambsquarters from lawns. Pre-emergent herbicides such as trifluralin (Preen) can be used to prevent germination of weed seeds. Post-emergent herbicides effective against broadleaf weeds are 2,4-D, MCPP and dicamba (sold under many brand names) and combination formulas (Trimec). Read labels to be sure the herbicide is effective against the weeds you want to eliminate and follow the directions carefully.
Photos: Judy Sedbrook
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010