Plant Information Return To Library Onopordum   Common Name: Scotch Thistle, Cotton Thistle, Cottonthistle, Onopordum   Family:   Asteraceae   Genus:   Onopordum   Species:     Cultivar:       Plant Description There are about 40 species in this genus of biennial thistles. Large gray leaves with spiny fingers grow on plants that can be 6'-8' feet tall. The thistle flowers are usually purple or white. While seemingly weed-like, this plant can make a striking plant in a border garden. Type of Plant Perennial Flower Zones Varies By Species Height Very High (over 5 feet) Spread Over 36" Bloom Time Summer Bloom Color Purple Plant Requirements Exposure Full Sun Soil Moisture Average Plant Characteristics and Attributes None Entered   Plant Propagation Seeds   Plant Notes Propagation and Division SEEDS: Some will self sow. DIVISION: Move seedlings around. NOTE: Biennial (short lived) Pruning and Maintenance MAINTENANCE: Prefers full sun and average well drained soil but can tolerate poor soil. Avoid wet winter. PRUNING: Deadhead after flowering. Clean up in fall.