Teasel is a biennial. The first year is spent as a flat rosette of leaves while it develops its root system. The second year, it grows branching stems up to 2 meters (6 feet) tall. The leaves are arranged opposite on the stem and the bases of two leaves form a basin around the stem that collects and holds up to 250 milliliters (8 ounces) of rain water. The inflorescence, an oval spike, grows at the tip of each branch.

Unlike most inflorescences that flower from the base upward, teasel spikes bloom with a ring of flowers about halfway up the spike. As the first flowers wither away, the next flowers open immediately above and below the old flowers. The spike continues flowering upward and downward so that the spike has two rings of blossoms until all the buds are spent.

Teasel was brought to North America with the wool industry. After woolen cloth was made, fullers 'fulled' (cleaned and thickened) the fabric. First the workmen rubbed fuller's earth, a mineral clay, into the woolens to remove oils and lanolin. The fuller's earth was shaken out and the fabric was stretched and then teased to raise a nap. The heads of teasel provided the right amount of teasing without damaging the weave.

The basin of water held by the leaves appears necessary to the formation of the spike. It is said that if this extra water is not present, the spikes do not form properly. The water is needed for the plant to form "perfect teasels".

(Compiled from: Hortus Third, Staff L.H. Bailey Hortorium, NY State College of Agriculture and Life Sciences, Cornell University, Macmillan, NY, 1976; The Herball, 1633 edition, John Gerard and Thomas Johnson, reprinted by Dover Publications, NY; A Modern Herbal, Mrs. M. Grieve, 1931, reprinted Dover Publications, NY, 1971; and "Common Summer Wildflowers of West Virginia", Norma Jean Venable, W.V. University Extension Service, West Virginia University)