Article Contributed on: 8/4/2006 10:58:18 PM
Teasel is a common name that refers to two species: Dipsacus fullonum, or common teasel, and Dipsacus laciniatus, cut-leaved teasel. Teasel, an alien invasive weed, may have been intentionally by introduced by the textile industry around 1700.
The genus name Dipsacus is derived from a word for thirst, and it refers to the way the plant's leaves wrap around the stem, forming a cup that traps rainwater. The common name teasel comes from use of the plant by the wool industry. Its stiff, sharp seed heads were used to 'tease' the fibers of wool, and raise the nap of cloth.
Why is it a problem?
Teasel is an aggressive rebel that takes over both prairie and pasture. Lack of natural enemies allows this exotic to proliferate. If left unchecked, teasel quickly forms large monocultures, forcing out all native vegetation. A single plant produces over 2,000 seeds, which remain viable for at least two years. The use of teasel in flower arrangements has aided its spread, especially in cemeteries.
What does teasel look like?
Teasel blooms are very distinctive. From July to September, hundreds of small purple flowers pop out and form a ring around the center of a large egg-shaped head. This ring grows in width over a few days, but since the flowers are short lived, the center of the booming section may die, leaving two rings of color, one growing towards the top and one towards the bottom of the flower cluster. Because of its unusual flower, teasel is often used as a horticultural plant.
The plant can grow to six feet tall and has a spiny stem. The leaves also have spines, hidden on the underside. Teasel is a biennial or monocarpic perennial. It grows from seed the first year, producing rosettes close to the ground, and then sends up a tall, flowering stalk the second year. After flowering, the plant dies, and the resulting striking stalks and heads may stand for several years.
What can you do to control this weed?
More prickly than thistle and armored like cactus, teasel is a formidable foe. You cannot take hold of a plant, anywhere, without being painfully stabbed. With proper protection, rosettes can be dug up using a dandelion digger. Like dandelions, remove as much of the root as possible to prevent resprouting. As an alternative, flowering stalks can be cut once flowering begins.
Bag and destroy all flowering stalks, because seeds still mature on stems even after cutting. Avoid cutting stalks before flowering, since the plant will send up a new flowering stalk. Herbicide is recommended where plants cannot be cut or dug-up. To learn more about control methods visit
http:// www.cepep.colostate.edu/profiles/common%20teasel.pdf
For information on natural resource issues, call the
Jefferson Conservation District at 720.544.2870. The mission of the Jefferson Conservation District is sensible management of natural resources and wise stewardship of the land.
Karen Berry is a member of the Jefferson Conservation District and the Wheat Ridge City Council.