Yellow Starthistle and Purple Starthistle

(Centaurea solstitialis and Centaurea calcitrapa)
Status: Non-native
Description: Yellow Starthistle is an annual plant with rough, bristly, lobed leaves. Its composite flowers are heads made up of many yellow flowers with spiny scale-like leaves. Purple Starthistle is an annual or perennial plant with deeply lobed, resin-dotted leaves. It has purple composite flower heads with spiny scale-like leaves. Both species range from 4 to 36 inches tall.
Growth Requirements: