IPMP3.0, Oregon State University, Copyright 2000

Biology and Management of Lambsquarter


Registered Herbicides

[Return to weed Identification]

[Return to Weed Management]



General Description:

  • upright annual (1-4 feet) with many branches.
  • mature leaves are alternate with a wavy margin on lower leaves.
  • soft gray coating on yong leaves and underside of mature leaves.
  • smal, sessile, inconspicuous gray-green flowers in dense clusters in leaf axils and branch tips.
  • rapid grower with high water use, very competitive.
  • short taproot is branched.
  • acts as a host for beet leafhopper which transmits curly top virus to beets.
  • edible, young growth is often included in salad greens.
  • Seedling: Cotyledons are linear, long, narrow, and are dark red on the underside. The first true leaves tend to be ovate to triangular, and are arranged altrenately.
  • Juvenile: Leaves are alternate, coarsely toothed, and ovate in shape. The leaves have petioles and the underside is covered with white mealy particles.
  • Mature: Lambsquarters has an erect growth form with alternate, coarsely toothed, ovate leaves. Grows 1 to 3 feet tall. The undersides of the leaves are covered with white mealy particles. Stems are grooved and have many branches.
  • Flowers: Flowers are greenish and indistinct. The flowers occur in clusters in the leaf axils.

Life cycle: annual

  • reproduces by seed, one plant may produce over a 1000 seeds.
  • seeds may persist in the soil profile for many years.
  • seedlings emerge in spring, early summer, and early fall.
  • flowers on spikes appear July - September.

Habitat/ Crops associated with:

  • does well on both acidic and alkaline soils.
  • found in cultivated and waste areas thoughout the U.S.
  • common in most horticultural crops.
  • found in sugarbeets, potatoes, mint, wheat, alfalfa, dry bean.

Herbicide Control Notes:

  • Goal often not adequate, and higher rates might cause crop injury. Widespread resistance to Sinbar. Usually emerges too late for effective control with Gramoxone.