Palmer amaranth, also known as Palmer pigweed, is an extremely aggressive, fast-growing species that has become a serious weed problem in vegetable and row crops in the southern half of the United States in recent years. It has also been introduced to Europe, Australia, and other areas. The plant is fast-growing (up to 1 inch a day) and highly competitive. It is adapted to heat and extremely low rainfall. Palmer amaranth is a tall, erect, branching summer annual, commonly reaching heights of 6–8 feet, and occasionally 10 feet or more. Male and female flowers form on separate plants (dioecious). This ameranth has rapid seed germination and growth and larger root structures than other species. One plant can produce up to 500,000 seeds. Cultivation and flaming are most effective on plants that are less than 1 inch tall.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day)
Soil drainage
Occasionally Dry | Very Dry
NC region
Coastal; Mountains; Piedmont
Growth rate
Rapid
Form & Appearance
Habit / form
Erect
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Elliptical; Lanceolate; Obovate; Ovate
Leaf margin
Entire
Leaf feel
Smooth
Leaf size
1-3 inches long, 1-3 inches wide
Hairs present
No
Leaf detail
Stems and foliage are mostly smooth and lacking hairs (glabrous). Leaves have fairly long petioles and are arranged symmetrically around the stem, giving the plant a distinctly poinsettia-like appearance when viewed from above. Petioles are longer than with common pigweed. Leaf-blades are elliptical to diamond-shaped with pointed tips, and measure 0.6–3 inches long by 0.4–1.5 inches wide. Some leaves may have a white watermark shaped like a 'V'.
Flower color
Green
Flower form
Spike
Flower size
3-6 inches
Flower detail
Inconspicuous flowers. Male and female flowers form on separate plants (dioecious). The flowers form on spikes up to 18 inches long. Female flowers are bristly to the touch and male spikes are softer.
Bloom time
Fall; Summer
Fruit color
Brown/Copper; Red/Burgundy
Fruit detail
The seeds (pyxis) are dark reddish-brown in color.
Stem detail
Stems and foliage are mostly smooth and lacking hairs (glabrous).
Wildlife & Ecology
Native status
Unknown
Origin
S. California to Texas and Mexico
Distribution
AR, AZ, CA, CO, FL, GA, IL, KS, KY, LA, MA, MD, MO, MS, NC, NE, NJ, NM, NV, NY, OH, OK, PA, SC, TN, TX, UT, VA, WI, WV
Food & Medicine
Edible parts
Leaves; Seeds
Edibility
The leaves and seeds are eaten. The seeds can be ground into a flour. The leaves can be cooked or dried.