Definition of horseweed
1 : a common annual American composite herb (Conyza canadensis synonym Erigeron canadensis) with an erect usually hairy stem and small discoid heads of yellow disk flowers
2 : a coarse annual North American ragweed (Ambrosia trifida)
Recent Examples of horseweed from the Web
Yet tolerance to 2,4-D has already been documented in several weed species that have elsewhere become glyphosate-resistant superweeds, including waterhemp and horseweed.
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First Known Use of horseweed
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