Plant Problem Diagnostic
Common Lambsquarters Identification and Control
The short answer
Common lambsquarters (Chenopodium album) is a summer annual with dull, pale gray-green leaves shaped like a goose's foot (variably triangular to lance-shaped) and, most distinctively, a fine white mealy or powdery coating that is heaviest on new growth and leaf undersides. It grows erect, up to about 5 feet, on stems that are sometimes striped purplish-red, with small petal-less green flowers in dense clusters.
The most useful ID is the mealy coating, because it separates lambsquarters from redroot pigweed, the weed it most often grows beside: pigweed has a pinkish-red taproot and coarse hairy stems and no mealy dust, while lambsquarters has the white powder and no red root.
It is a problem because it is prolific: a single plant can produce tens of thousands of seeds that stay viable in the soil for years, and late-emerging plants can begin setting seed within six weeks even when small. So the control that matters is removing seedlings before they seed, by pulling or hoeing, or mowing plants before they flower.
How to identify it
Start with the powder. Young leaves and new growth carry a distinctive white, mealy coating from tiny hairs, so a fresh shoot looks dusted with flour; the leaves themselves are dull pale gray-green, roughly goosefoot-shaped but variable from triangular to lance-shaped, and 1 to 5 cm long. Seedling cotyledons are narrow and oblong, bluish-green above and often purplish-red beneath.
The mature plant stands erect up to about 5 feet on a single or few-branched stem that is sometimes striated purplish-red, topped with dense clusters of small, stalkless, petal-less green flowers. It reproduces only by seed.
Lambsquarters or pigweed?
These two summer annuals routinely come up together, and telling them apart guides your expectations for the seed bank. Lambsquarters shows the white mealy coating on new growth, has smooth (not hairy) stems, and lacks a colored taproot. Redroot pigweed has no mealy dust, coarse and often hairy upper stems, prickly seed spikes, and the pinkish-to-red taproot that gives it its name.
Both are prolific seeders best removed young, so the practical management is similar, but the mealy coating is the quick tell in the field.
Control, and a note on eating it
Get it before it seeds. Because a single plant can set tens of thousands of seeds that persist in the soil for years, and even small late plants can seed within six weeks, the effective control is pulling or hoeing seedlings and young plants while small, and mowing plants before they flower where hoeing is impractical. Persistence over a few seasons is needed to draw down the seed bank.
The young leaves and shoots are edible and sometimes harvested as a green, which conveniently doubles as removing the plant before it seeds. But note that lambsquarters contains saponins and oxalic acid, so it should be cooked (steamed) rather than eaten raw in quantity, and older parts are mildly toxic raw. If you consider a herbicide, be aware Extension reports documented resistance in this species to certain herbicide classes; follow the label and county Extension guidance, as no rates are given here.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- UC IPM - Common Lambsquarters (Weed Gallery) — Common lambsquarters (Chenopodium album) is a summer annual reproducing by seed; cotyledons are narrow, oblong to lance-shaped 4-15 mm long, dull bluish green above and often purplish red below, developing a white powdery coating; mature plants grow up to 5 feet tall with dull pale gray-green triangular to lance-shaped leaves 1-5 cm long bearing a fine white powdery coating, on single or few-branched stems sometimes striated purplish red; petal-less green flowers bloom May through November producing tiny black and larger brown seeds.
- Cornell University Weed Identification - Common Lambsquarters — A single common lambsquarters plant can produce thousands of seeds germinating 0.5-3 cm deep; young plants have a grayish-white powdery coating on cotyledons, leaves and stems; late-emerging plants can begin to set seed within six weeks even on very small plants; herbicide resistance has been documented since 1975 to both Photosystem II inhibitors and ALS inhibitors.
- NC State Extension Gardener Plant Toolbox - Chenopodium album — Chenopodium album is a summer annual with goose-foot-shaped variable leaves and a white mealy coating from tiny hairs, producing copious amounts (50,000 or more) of tiny seeds; young leaves and shoots are edible but contain saponins and oxalic acid so must be cooked/steamed/frozen and older parts are mildly toxic raw; pulling seedlings before they set seed or mowing before seed production are two management options, and seeds can remain viable in the soil for many years.