TEASEL...A PRICKLY PEST
DESCRIPTION:
Teasels are monocarpic perennials. The plant grows as a basal rosette for a minimum of one year, then sends up a tall, flowering stalk and dies after flowering. The rosette stage varies according to the amount of time needed to acquire enough resources for flowering to occur.
During the rosette stage, leaves change from being somewhat ovoid in the younger stage to large, oblong, and quite hairy in the older stage. During the rosette phase, teasel develops a large taproot. The taproot may be over 2 feet in length and 1 inch in diameter at the crown.
Common teasel blooms from June through October. Flowering plants have large, oblong, opposite, sessile leaves that form cups (the cups may hold water) and are prickly, especially on the lower midrib. Teasel's unique inflorescence makes the plant readily identifiable when flowers or seedheads are present. Flowers are small and packed in dense, oval-shaped heads. The flowers are subtended by stiff, spiny bracts that are located terminally on the flowering stems. Common teasel generally has purple flowers. Flowering stems may reach 6-7 feet in height. But white flowers can also be present.
Life History and Effects of Invasion