Amaranthus palmeri

Scientific Name Amaranthus palmeri - S.Watson.
Common Names English : Palmer's Amaranth, Palmer Pigweed, Carelessweed; German: Fuchsschwanz-Amarant, Palmer Amarant; Spanish: Quelite de aguas, quelite; French: Amarante de Palmer
Description An erect summer annual that may reach 2 m (6.56 ft) in height. Taproot often reddish in color.

Descriptions

Characteristic Features

Dense, compact terminal panicles and relatively tall plants with alternately arranged leaves with petioles that are longer than the leaves.

Young Plant

Stems below the cotyledons (hypocotyls) are without hairs (glabrous) but sometimes slightly hairy, and often red in color. First true leaves are alternate, ovate in shape, and slightly notched at the tip of the leaf blade (apex).

Cotyledons

Narrow (10 to 12 mm; 0.39 - 0.47 inch) long and green to reddish on the upper surface. Lower surfaces of cotyledons have a reddish tint.

Stems

One central stem occurs from which several lateral branches arise.

Leaves

Alternate, without hairs (glabrous), and lance-shaped or egg-shaped in outline. Leaves are 5 to 20 cm (1.97 - 7.87 inch) long and 2-6 cm (0.78 - 2.36 inch) wide with prominent white veins on the undersurface. Leaves occur on relatively long petioles.

Propagatio Organs

Flowers

Small, green, inconspicuous flowers are produced in dense, compact, terminal panicles that are from 15 - 45 cm (5.9 - 17.7 inch) in length. Smaller lateral inflorescences also occur between the stem and the leaf petioles (leaf axils). Male and female flowers occur on separate plants. Each terminal panicle contains many densely packed branched spikes that have bracts that are 3 to 6 mm (0.12 - 0.24 inch) long.

Flowering Period

June - November.

Fruit

A single seeded utricle, 2 mm (0.078 inch) in length and wrinkled when dry. Each utricle splits open in the middle to expose the seed.

Seeds

Single glossy black to dark brown, 1 to 1.2 mm (0.039 - 0.047 inch) long. Main germination period is in spring.

Viability Of Seeds

Tens of thousands to hundreds of thousands persistent seeds per plant.

Propagation

By seeds.

Occurrence

Habitat

Open areas with full sun and disturbed areas, agricultural fields.

Soil

Disturbed soils.

Additional Crop Information

Soybean, peanuts.

Agricultural Importance

Palmer amaranth is among the five most troublesome weeds in cotton, peanut, and soybean throughout the Southeast US. A. palmeri shows competitive interference on cotton development, yield, and fiber properties. The resistance to herbicides, such as glyphosates, dinitroanilines and ALS- inhibitors limits the options to control the weed.

Related Crops

Choose directly from Category

Pests

Pests

Search directly for a particular pest

Diseases

Diseases

Search directly for a particular disease

Weeds

Weeds

Search directly for a particular weed

Choose by Crop