Flower:

One to several short-stalked or stalkless thistle-like flower heads clustered at the tips of branches and arising from the leaf axils. Flowers are ½ to ¾ inch wide, light lavendar to deep violet or rarely white, with dark purple-tipped stamens surrounding a white style and extending above the disk flowers. Surrounding the flower is a dense, round array of softly spiny bracts with tiny hooks at the tips.

Leaves and stems:

Leaves are alternate, coarse and densely hairy. Basal leaves are broadly heart-shaped with rounded tips, have long hollow stalks, wavy edges, are up to 2 feet long and over a foot wide, becoming smaller, stalkless and less wavy up into the flower clusters. Stems are stout but brittle and green or reddish purple, hairless to sparsely hairy.

Fruit:

Fruit is a head of light brown seeds with a few short bristly hairs attached. The bracts dry to brown and become stiff, the hooks attaching the seed head to clothing, animal fur, and anything that passes by, spreading seed far and wide.

Notes:

Burdock is a tenacious weed with a massive taproot that does not respond well to herbicide control, plus it has a persistent seed bank. The hooked fruits are reputed to be the inspiration for Velcro. The leaves are similar in size and shape to rhubarb, causing more than a few people to refer to it as wild rhubarb. It is very likely in every Minnesota county, though it has not been recorded in several counties.