Common and cutleaf teasel Dipsacus fullonum L. and D. laciniatus
Family: Dipsacaceae (teasel)
Life cycle: Monocarpic perennial (Rosette stage may persist for more than one year, but the plant dies after it flowers)
Native status: Introduced to N. America
Habitat: roadsides, pastures, waste areas
General description: Basal leaves on the rosette are widest near tip and taper to the base, ‘wrinkled’, with rounded teeth. Flowering plants reach heights of 7 ft, stems are angled and covered with downward turned prickles. Leaves on bolted plants are opposite, lanceolate, up to 2 ft long with spines on underside of midrib. Flower heads are cylindrical up to 4” long and 2” wide. Tubular corollas are white to light purple in color. The heads are surrounded by long spine-like bracts.
Key ID traits: Bristly stem, large lanceolate leaves with spiny midrib. The dead flowers are spiny and persist through the winter.
Similar species: Cutleaf teasel has a similar growth habit to common teasel but has lobed leaves with spines on the margins.
Miscellaneous: Teasel is currently invading Iowa, moving northward in the state. It is relatively rare in central and northern parts of the state. The distinctive flower heads are commonly used in dried flower arrangements. Common teasel is on the Iowa Noxious Weed List. In the 1950’s and 60’s, ISU’s extension weed scientist was notorious for going to county fairs and confiscating flower arrangements that used teasel due to the presence of viable seeds in the teasel heads.