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Redroot Pigweed

Pest Profile: Redroot Pigweed

Redroot pigweed is an annual broadleaf weed that has developed resistance to Group 2 herbicides in Western Canada, and Group 5 resistance in the U.S. and Ontario. While the plant is a poor competitor, especially with established plants, it can still significantly reduce yields in less competitive crops, like flax and pulses. One plant can produce more than 100,000 seeds in a season, which stay viable for up to five years, so it’s important to scout early and use multiple modes of action for effective control.
Redroot Pigweed



  • Annual
  • Broadleaf


Plants have a long, fleshy, reddish to pink taproot and stems that are erect, light green, branched, 23-35 inches high, rough and angular. The leaves are alternate, stalked, dull green, oval-shaped, rough and 3-4 inches long. Plants have numerous flowers that are small, green and crowded into dense, finger-like spikes.


  • Redroot pigweed seeds prefer warm temperatures of 20ºC or higher for germination.
  • Crops established before soils warm and weather sets in are very competitive with this weed.
  • Watch growth stages carefully under hot conditions because the plant can quickly advance beyond the recommended stages for herbicide application.


Please read each label to determine which herbicide is appropriate for the crop affected.