Redroot Pigweed

Biological Name:

Amaranthus retroflexus (Redroot-Pigweed)

Natural Habitat:

Redroot-Pigweed: This plant is a type of weed that is native to North America, and it typically grows in disturbed areas such as fields, gardens, roadsides, and waste places. It can also be found in cultivated areas and along the edges of forests and woodlands.


Redroot-Pigweed is a small green weed that is often found in gardens and lawns. It has a distinctive red root which gives it its name. This weed is often mistaken for other plants such as lamb’s quarters or pigweed because it can grow to be quite tall and has small white flowers. It is typically found in areas with poor soil and is often considered a nuisance weed because it can be difficult to remove.

Frequently Asked Questions (FAQs)

Q: Is redroot pigweed an invasive plant?
A: Daily home & garden tip: Pigweed is an invasive weed, but it’s edible.

Q: Can you eat redroot pigweed?
A: The leaves of pigweed are also incredibly nutritious. They’re high in vitamins A and C and folate, as well as calcium. In Jamaica, pigweed is known as callaloo and is a culinary staple.

Q: What is redroot pigweed good for?
A: Consuming pigweed can help alleviate fever, headache, nausea, stomachache, and other digestive disorders. Moreover, pigweed leaves have astringent properties. For that reason, tea made from these leaves can help treat sore throat, heavy menstrual bleeding, diarrhea, internal bleeding, and internal ulcers.

Q: What part of pigweed is poisonous?
A: Pigweed (Amaranthus retroflexus) is a common annual weed found throughout the United States. The weed can grow three to four feet; the flowers are green and prickly and the plant has oval shaped leaves. The pigweed’s leaves, roots and stems are toxic.

Q: Should you pull pigweed?
A: If pigweeds are in the advanced reproductive stage and might drop viable seed when handled, carefully bagging plants is even more important, Farr and others say. Guy Collins, cotton Extension associate professor at North Carolina State University, also advocates hand pulling.

Q: What does pigweed tell you about your soil?
A: Redroot pigweed (Amaranthus retroflexus) indicates that the soil is heavily compacted by either heavy foot traffic or just high clay content. Compaction is a sign of low aeration, meaning lower oxygen for roots, soil microbes, water logging and undeveloped root system.

Q: Is pigweed poisonous to dogs?
A: Amaranth greens, sometimes called pigweed, are toxic for dogs because of oxalates and nitrates that are present in the vegetable. If consumed, oxalates and nitrates can cause kidney failure in dogs.

Q: Is amaranth the same as pigweed?
A: Pigweeds are major weeds of warm season vegetables (Webster, 2006) and row crops (Sellers et al., 2003). Also called amaranths, pigweeds are native to parts of North and Central America.

Q: Is amaranth toxic?
A: Avoid eating too much amaranth from agricultural fields. The leaves (like those of spinach, sorrel and many other greens) also contain oxalic acid, which can be poisonous to livestock or to humans with kidney issues of eaten in large amounts.

Q: Why did the Spanish ban amaranth?
A: In the 16th century the Spanish conquistadors banned the plant’s cultivation, fearing that the spiritual connection with it would stymie the establishment of Catholicism on the continent. But the Incas and Mayans continued to grow amaranth.

Q: Is redroot pigweed a summer annual?
A: Redroot pigweed, a summer annual broadleaf plant, is found up to 7900 feet (2400 m) in the Central Valley, northwestern region, central-western region, southwestern region, Modoc Plateau, and most likely in other California areas. It thrives in open, sunny places inhabiting agricultural land other disturbed places.

Q: Should I remove pigweed?
A: If you spot pigweed plants that have yet to produce mature seeds, pull them or cut them off just below the soil line. Plants with mature seeds should be bagged before being removed and destroyed. Either burn the plants or bury them under at least a foot of compost.

Q: Why is pigweed so difficult to control?
A: The researchers have determined a specific genetic feature, the extrachromosomal circular DNA (eccDNA) replicon, gives pigweed, or glyphosate resistant palmer amaranth, its resistance to glyphosate and makes this weed difficult to control.

Q: What damage does pigweed do?
A: Gross lesions of pigweed toxicosis include widespread edema, most prominently around the kidneys, rectum and omentum. Kidneys are pale and normal to swollen in size. Histopathologic changes within the kidney include interstitial edema, scattered hemorrhages and proximal tubular degeneration and necrosis.

Q: How is pigweed spread?
A: The aggressive weed can produce a million seeds from a single plant. It can infest farms through seeds carried on second-hand farm equipment, by combine harvesting, in livestock feed, or even by being blown into farms from roadside mowing.

Q: How do I control pigweed in my garden?
A: One of the best ways to prevent spiny pigweed is by using a pre-emergence herbicide containing the active ingredient trifluralin. Treflan is one of the well-known brands, Preen and Eliminator also make trifluralin products. Pre-emergent herbicides work by preventing weed seeds from germinating.

Q: How do you control redroot pigweed?
A: Rotary hoeing: Pigweeds are easily controlled with a rotary hoe when less than 1/4″ in height. Flaming: Flaming is very effective on small pigweed plants (less than 1.5″” in height). Crop rotation: Small grains suppress redroot pigweed in the rotation.”

About the author

Samuel is a gardening professional and enthusiast who has spent over 20 years advising homeowners and farm owners on weed identification, prevention and removal. He has an undergraduate degree in plant and soil science from Michigan State University.