Common Burdock (Arctium minus (Hill) Bernh.)
Common burdock is a biennial or occasionally short-lived perennial that develops from a large taproot. During its first year, it forms a basal rosette of leaves close to the ground. In its second year, it sends up thick, erect flowering stems that grow 3–7 feet tall. Stems are grooved, sturdy, and range from green to purple.
Leaves are large, egg- to heart-shaped (cordate) with wavy or toothed margins and noticeable pale white to pinkish veins. The upper surface is green, while the underside is densely covered with woolly white hairs. First-year leaves may be modest in size, but second-year leaves can grow up to 12 inches long. Leaves are arranged alternately along the stem, becoming smaller and more widely spaced toward the top. Petioles are long and hollow.
Common burdock is often mistaken for rhubarb due to its large leaves and similar growth habit; however, rhubarb leaves and stems are smooth (glabrous), while burdock leaves are hairy underneath.
Flowering occurs from early summer through early fall. Flowers are borne in clusters (panicles) at the ends of stems. Each flower head is enclosed in a round bur approximately 1 inch across, with hooked bracts that cling to animals, clothing, and equipment. Pink to purple (occasionally white) tubular florets emerge from the top of each bur. These burs persist on dried stalks and were the inspiration for the invention of Velcro. Seeds are small (about 6 mm), ridged, and enclosed within the burs.
Quick ID Guide
Life Cycle:
• Biennial (rosette first year, flowering stalk second year)
• Large taproot
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Height:
• 3–7 feet tall in the second year
Leaves:
• Large, heart- to egg-shaped
• Wavy or toothed margins
• Green above, woolly white beneath
• Up to 12 inches long
• Long, hollow leaf stalks
Flowers (Early Summer–Early Fall):
• Pink to purple (sometimes white)
• Clustered at stem ends
• Enclosed in round, hooked burs (~1 inch wide)
Seeds/Fruit:
• Hooked burs cling to animals and clothing
• Small, ridged seeds inside
Management Options
Prevention and early detection are the most effective management strategies for common burdock. Maintain healthy, competitive vegetation to reduce establishment, and monitor disturbed areas regularly. Remove plants before they produce seed to prevent further spread.
There are currently no approved biological control agents available for common burdock.​
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Hand pulling or digging can be effective, particularly for first-year rosettes, as long as the entire taproot is removed. Removal is easiest when soils are moist. Second-year plants should be controlled before flowering and seed set. Cutting flowering stalks before bur formation can help reduce seed production; however, plants may resprout if not completely removed. Mowing can suppress second-year plants if repeated and timed before flowering.
Herbicides can be effective, especially when applied to actively growing rosettes in the spring or fall. Applications made before flowering provide the best results. Always read and follow the herbicide label before use. Contact Sublette County Weed & Pest for assistance with product selection, rates, and application timing. ​
