Family: Teasel Family (Dipsacaceae)
Origin and Distribution: Common teasel was imported from its native Europe into North America, possibly as an ornamental or more likely because the dried flowers were used in wool production. Its current range is limited and includes areas in the northeastern U.S., the Pacific Coast, and southern Canada. Common teasel occurs throughout Ohio where it is found in pastures, abandoned fields, roadsides, railroads, and waste areas. The species prefers damp, coarse and fertile soils.
Plant Description: Common teasel is a biennial member of a genus distinguished by the manner its leaves are fused around the flowering stem forming a cup that collects rainwater. Common teasel produces puckered leaves with scalloped edges in the form of a rosette during its first year of growth after which a 6-foot-tall prickly flower stem emerges. Flowering stems are usually branched at the top and cone-shaped flower clusters form at the ends of the branches. Below each cluster and curving upward around it are several stiff bracts. In each cluster are many short bristles interspersed with individual flowers consisting of white petals united into a tube with 4 purple lobes. Stems and flowers become woody and persist through the following winter and sometimes over several seasons. Reproduction is by seeds.
- Root system - The plant has a thick taproot and fibrous secondary roots.
- Seedlings & Shoots - Young leaves have toothed edges, a puckered surface, and are shape similarly to an egg. Leaves persist over winter as a basal rosette.
- Stems - Flowering stems are 2 to 8 feet tall, erect, angled, furrowed, branched near the top, and prickly. The pithy stems become woody and may persist for several years.
- Leaves - Shiny green rosette leaves have scalloped edges, scattered stout hairs on the upper surface, and are attached to the stem by way of a leaf stalk (petiole). Leaves on the flowering stem are similar to rosette leaves except they are smaller, opposite (2 leaves per node), and have short spines on the underside of the midrib. Rather than attaching to the stem by way of a petiole, the bases of stem leaves are fused around the stem forming a cup in which rainwater collects.
- Flowers - Flowers form in cone-shaped, spiny clusters. Individual flowers, which are 2/5 to 3/5 inch long, consist of white petals united into a tube with 4 purple lobes. Below each cluster are several long, slender, stiff, bracts that curve upward. Within the cluster, there are many short, stiff bristles. Once mature, flower clusters becomes dry, hard, and persistent.
- Fruits & Seeds - Fruits are light brown, about 1/5 inch long, ridged, hairy, and 4 angled. Enclosed in each fruit is a single seed.
Similar Species: Cutleaf teasel (Dipsacus laciniatus) can be distinguished from common teasel by its deeply-lobed leaves. Common teasel flowers resemble those of several thistle genera, but its leaves are puckered and have spineless edges and it grows for at least a year as a basal rosette.
Biology: Common teasel blooms from July to September. The first flowers to open are located in a ring around the center of the cluster. Then, bands of flowers above and below this ring bloom simultaneously. Some plants produce flowers after growing for one year as a rosette while others take 3 or more years to flower. Researchers found that leaf size predicted the onset of flowering more consistently than plant age; once leaves exceeded 5 inches, there was an 80% chance the plant would flower during the following season. Seeds usually fall within 5 feet of the mother plant. Goldfinches and blackbirds have been observed feeding on common thistle seeds, so it is possible that some seeds are dispersed by birds. An average teasel plant produces 3300 seeds. Common thistle does not survive disturbances such as cultivation.
Toxicity: None known.
Facts and Folklore:
- 'Dipsacus' was derived from the Greek verb meaning "to be thirsty", which is likely in reference to the water-collecting cup formed by the stem leaves.
- The weed's common name refers to the practice of using the flowers to tease wool. The common names 'card teasel' and 'card-thistle' are in reference to the wire brush or "card" used to tease wool.
- Teasel is often added as a dried plant to ornamental arrangements.