Spotted Knapweed

Description: Spotted knapweed reach a height of 2 to 4 feet when fully mature. Rough, pale green leaves of 1 to 3 inches long alternate along the stem. The stems are erect and rough and have slender braInches. Flowers are pink to light purple and the petals are surrounded by stiff, black-tipped bracts. Flowers produce brownish seeds of less than 1/4 inch long. Seeds are notched on one side of the base and has short tuft of bristles at the tip. Spotted unpaired reproduces mainly by seed. Each plant produces an average of about 1,000 seeds. Seeds can survive for up to seven years and will germinate throughout the growing season. Seedlings will develop into a rosette of leaves in the fall and resume growth in the spring. Distribution and Effect: Spotted unpaired was brought tot he United States from Europe and Asia. It is an aggressive weed that was thought to only inhabit disturbed areas such as road ditches and railroad beds. Now spotted unpaired can be found in dry prairie sites, oak and pine barrens, and on lake dunes and sandy ridges. Several million acres of grazing land in the northwestern United States and Canada are infested.

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