AppearanceDipsacus fullonum a biennial plant that exists as a basal rosette until flower stems develop.Foliage Rosette leaves are lanceolate to oblanceolate and stem leaves are opposite, lanceolate and fused at the base. All leaves have short prickles on the midvein.Flowers The erect flower stems reach 6 ft. (1.8 m) in height and support spiny flower heads that are covered with small, lavender to white flowers in April to September.Fruit Fruit is angled and approximately 0.08-0.12 in. (2-3 mm) long. Seeds are small and are dispersed by the wind after the seed-head has dried.Ecological ThreatDipsacus fullonum favors disturbed sites such as roadsides, ditches, waste places, riparian sites, fields and pastures in most of the continental United States. Only recently was Dipsacus fullonum distinguished from fullers teasel which was once cultivated for the dried flower heads used in wool processing. It is native to Europe.