Common Teasel (Dipsacus fullonum)

Gallery:

Common teasel persistent dead flower heads

Common teasel rosettes

Common teasel leaf

Common teasel flower head

Common teasel, bolting stem and leaves

Common teasel infestation

Common names:

Common teasel, fuller’s teasel, teasel, venuscup teasel

Scientific Name:

Dipsacus fullonum

Description:

Common teasel is a biennial plant in the Dipsacaceae (teasel) family. It is considered invasive across North and South America. The roots are stout and deeply taprooted and the stems are ridged and either hollow or pithy. Teasel grows as a rosette the first year (sometimes more than one year), and then dies after it flowers and sets seed the following year. The flowers are very dense, prickly, and can be 4 inches tall. There are distinctive spiny bracts under the flower head that curve upward and extend above the flower head. The leaves are opposite and long, with wavy margins and spines on the underside along the midvein. After it sets seed, the old flower heads can remain, containing viable seeds. It spreads through its seeds which can be transported by wildlife, soil movement, and mowing.

Life cycle:

Biennial to short-lived perennial

Height of mature plants

up to 6 or 7 feet tall

Flower color:

pink to purple (occasionally white)

Bloom time:

April to September

Look-a-likes:

Two other species of teasel are similar to common teasel: cutleaf teasel (D. laciniatus) and fuller’s teasel (D. sativus). However, both D. fullonum and D. sativus are often referred to as Fuller’s teasel as both have been used in the fulling process to make woolen cloth. Both of these similar species typically have white flowers, and the bracts underneath the flower heads are typically shorter than common teasel, whose bracts curve upward and reach above the flower head. Cutleaf teasel also has lobed leaves on the stem, while common teasel’s leaves are unlobed.

Habitat:

Common teasel grows best in sunny open habitats, and can tolerate wet to dry conditions. It is often found growing along roadsides and abandoned fields, but can also be found along the margins of wetlands, ponds, and streams. More recently it has been invading agricultural areas.

Impacts:

Common teasel can create dense stands and in open, sunny habitats, it can out-compete native grasses and agricultural plants. Large populations can be difficult to control because each plant can produce up to 34,000 seeds, and the taproots can be up to 2 feet long. It is often spread through mowing practices as old seed heads often contain viable seeds. However, small populations and young plants are easier to control.