Arctium minus, commonly known as lesser burdock, little burdock, louse-bur, common burdock, button-bur, cuckoo-button, or wild rhubarb, is a biennial plant. This plant is native to Europe, but has become introduced elsewhere.
Arctium minus can grow up to 1.5 meters (1 to 5 feet) tall and form multiple branches. It is large and bushy. Flowers are prickly and pink to lavender in color. Flower heads are about 2 cm (0.79 in) wide. The plant flowers from July through October. The flowers resemble and can be easily mistaken for thistles, but burdock can be distinguished by its extremely large (up to 50 cm) leaves and its hooked bracts. Leaves are long and ovate. Lower leaves are heart-shaped and have very wavy margins. Leaves are dark green above and woolly below. It grows an extremely deep taproot, up to 30 cm (12 in) into the ground. Invasive in the US.