IPMP3.0, Oregon State University, Copyright 2000

Redroot Pigweed
Amaranthaceae (Amaranthus retroflexus)


Biology and Management

Registered Herbicides

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Redroot Pigweed Seedling (link to large image)

Redroot Pigweed Flowers (link to large image)

Redroot Pigweed Seedling Redroot Pigweed Flowers

Redroot Pigweed Mature Plant (link to large image)

Redroot pigweed is a summer annual that reproduces only by seed. Seeds are glossy black, rounded with convex sides.  Seeds are produced late summer through fall. Seeds germinate spring through summer. Mature plants grow upright 2 to 3 feet tall. The lower stem and taproot are reddish colored. Leaves are alternate and simple.  Leaves are reddish-green with long petioles and prominent veins. The flowers are green arranged in dense terminal clusters. This species acts as a host for beet leafhopper that transmits the virus of curly top in beets. This weed occurs throughout the west and is associated with cultivated soils, gardens, and waste areas. It was introduced from tropical America and thrives in warm climates.
Redroot Pigweed

Mature Plant


This section contains information on identification of the different life stages of Redroot Pigweed.  Select Biology and Management from the Contents Menu for more information on the biology and management, or select Registered Herbicides for the herbicides that are registered to control this weed in mint.