Common Teasel

Weed Description: An erect biennial with small prickles on the stem and distinctive spiny flower heads. Common teasel may reach 6 1/2 feet in height and is primarily a weed of roadsides, pastures, hayfields, and occasionally rosettes can be found in turfgrass. This weed is found throughout the United States except in the northern great plains.

Seedling: Cotyledons are oval to round in shape and occur on short petioles. First true leaves are also oval to round in shape, have rounded or 'scalloped' teeth, and have an overall wrinkled appearance.

Leaves: Plants initially produce a basal rosette of leaves and then flowering stems are produced during the second year. Rosette leaves are oval in outline, have a wrinkled appearance, and have margins with rounded or 'scalloped' teeth. Leaves that occur on the flowering stems are opposite, without petioles (sessile), and are lanceolate in outline. Leaves that occur on the flowering stems are also 'clasping', with their leaf bases completely surrounding the stem. All leaf midveins have short prickles on them.

Stems: Flowering stems are produced during the second year of growth and are erect and branching near the upper portions of the plant. Stems are angled and also have many small prickles that are turned downward on them.

Fruit: An achene that is angled and approximately 2 to 3 mm long.

Flowers: Flowers are egg-shaped in outline but cut off squarely at the base. Flowers are approximately 1 1/4 to 4 inches long and consist of many individual white to lilac flowers that bloom in a circular pattern around the seedhead. Individual flowers are from 10 to 15 mm long and occur on flower stalks (peduncles). Several long, leaf-like bracts also branch out from the base of the flower and curve upward around the head.

Identifying Characteristics: Leaves with a 'wrinkled' appearance, stems with small prickles curving downward, and large spiny flower heads are all characteristics that help to distinguish common teasel from other weed species. When in the rosette stage of growth, however, common teasel might be mistaken for a thistle, Common Burdock (Arctium minus), or Broadleaf Dock (Rumex obtusifolius), but neither of these weeds have leaves that are 'wrinkled' like those of common teasel.