Prostrate Pigweed (or Mat Amaranth)

Scientific Name: Amaranthus albus

Plant Family: Amaranthaceae

Native Region: Native to central and eastern North America; now naturalized worldwide in temperate and tropical regions.

Prostrate Pigweed (or Mat Amaranth)

Brief Description

A low-growing, sprawling annual herb with light green, oval to egg-shaped leaves that often have wavy margins and a small notch at the tip. The stems are typically pale green to whitish.

Care Instructions

This is often considered a weed and requires little care. It thrives in disturbed soils with full sun and occasional watering. It does not require fertilizer in most garden conditions.

Medicinal Value

We do not currently provide medicinal value for plant identifications.

Sunlight

Full sun (6-8+ hours per day); it is highly light-responsive and grows poorly in heavy shade.

Watering

Moderate to low. It is drought-tolerant once established but grows more vigorously with regular moisture. Overwatering can lead to root rot.

Soil

Prefers well-drained, sandy, or loamy soils with a neutral pH, though it can tolerate poor, compacted, and disturbed soils.

Hardiness Zone

Annual; grows in USDA zones 3-11 during the frost-free season.

Growth Habit

Summer annual. It has a prostrate, branching growth habit forming mats on the ground. Can reach 6-20 inches in height and spread up to 2-3 feet.

Bloom Season

Mid-summer to early autumn. Flowers are small, greenish, and inconspicuous, growing in dense clusters in leaf axils.

Toxicity

Generally non-toxic, but plants grown in nitrogen-rich soils can accumulate nitrates, which can be harmful if consumed in large quantities by livestock. Contains oxalates, which should be avoided by those with kidney stones.

Propagation

Propagates solely by seed. Each plant can produce thousands of seeds that remain viable in the soil for years.

Common Pests & Issues

Commonly affected by flea beetles, cucumber beetles, and aphids. It can also host viruses that affect vegetable crops like tomatoes and peppers.

Similar Species

Amaranthus blitoides (Prostrate Amaranth) and Amaranthus retroflexus (Redroot Pigweed). It is distinguished from the latter by its low, spreading habit versus the upright growth of Redroot.

Interesting Facts

Also known as 'tumbleweed' because the plant can break off at the base when dry and roll with the wind to disperse its seeds across large distances.

Created At: 2026-05-26T01:13:23.650347