Burdock species are biennial, herbaceous plants in the Aster family (Asteraceae). In Ontario, there are three recognized species: common burdock (Arctium minus), greater burdock (A. lappa), and woolly burdock (A. tomentosum). Petitie bardane, grande bardane and bardane tomenteuse are, respetively, the three French common names. All three are weedy species that share similar histories and biology, with some differences in identification features. Once established, burdock species become difficult to eradicate as their thick, deep taproot is challenging to remove. In addition, each common burdock plant can produce between 6,000 to 17,000 seeds, yielding a substantial seed bank. The basal leaves of burdock in its second year are large and can shade out native plants, reducing diversity and altering community composition. The bristly seed heads of these plants pose a threat to small birds and bats that can become entangled and die.

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