Common and Cut-leaved Teasel

Dipsacus fullonum (sylvestris), D. laciniatus

DESCRIPTION:

Teasels are non-native biennials or short-lived perennials, that grow as a rosette for a minimum of one year, send up a tall flowering stalk and then die after setting seed. During the rosette stage teasels develop a large taproot that may be over two feet in length and an inch in diameter.

When flowering, teasels can reach a height of 7 feet. Both species have flowers packed in a dense oval shaped inflorescence on top of a spiny stem. Common teasel has pink or purple flowers, undivided leaves and bracts that are longer than the flowering head. Cut-leaved teasel has deeply lobed leaves and white flowers. A single teasel plant can produce approximately 3,000 seeds.

HABITAT:

Teasels thrive in open sunny conditions in mesic to dry habitats. Cut-leaved teasel is often found in wetter soils than common teasel; both tolerate saline conditions. Teasels are commonly found in abandoned fields, along roadsides and in cemeteries. They can invade prairies, savannas, sedge meadows and moist forest openings.

DISTRIBUTION:

Teasels are native to Eurasia and northern Africa. Introductions were probably made by early settlers deliberately as ornamentals or accidentally as toys made from the flowering heads. Teasels were also used commercially for combing wool. Common teasel is distributed throughout the United States (excluding the far north central states). Cut-leaved teasel currently has a more restricted range, primarily occurring in the northeastern and Midwestern states. Both species are found throughout Ohio, although common teasel is more abundant.

PROBLEM:

Teasels produce massive amounts of seed that can remain viable in the soil for several years and have germination rates as high as 86%. In addition, the death of a mother plant leaves behind an excellent "nursery" for new seedling establishment leading to a continuous population of dense monocultures. The combination of these life history traits enable teasels to successfully outcompete native plants.

CONTROL:

Mechanical

Individual rosettes can be removed using a dandelion digger; removal of the entire root is essential to eliminate re-sprouting. Flowering stalks may be cut down once the plant has initiated flowering, but if cut too soon plants may send up new flowering stalks. It has been shown that seeds will continue to develop and mature even after cutting. To prevent seed dispersal, the cut stalks should be removed.

Chemical

Foliar application of herbicides is effective and useful when mechanical treatments are not feasible. Herbicide, such as RoundupÂ®, GlyproÂ®, or TranslineÂ® should be applied to the rosette stage. In natural areas, application during the late fall or early spring will result in less harm to non-targeted species.

Biological

No biological control methods are currently available.

ADDITIONAL INFORMATION SOURCES:

Huenneke, L.F. and J.K. Thomson. 1995. Potential interference between a threatened endemic thistle and an invasive nonnative plant. Conservation Biology 9(2): 416-425.

Solecki, M.K. 1991. Cut-leaved and common teasel: profile of two invasive aliens. Biological Pollution: The Control and Impact of Invasive Exotic Species. Indiana Academy of Science, Indianapolis, Indiana, USA.

Werner, P.A. 1975. The Biology of Canadian Weeds: Dipsacus sylvestris. Canadian Journal of Plant Science 55: 783-794