Purple/Iberian Starthistle
Centaurea calcitrapa and C. iberica
Description
Mature purple starthistle grows one to four-feet tall and is densely, rigidly branched. Young stems and leaves are covered with cobweb-like hairs that disappear with age. Rosette leaves are deeply lobed and older rosettes have a circle of spines in the center. The lavender to deep purple flower is atop a bract with straw-colored spines and one to three pairs of lateral prickles at the base. Iberian starthistle is very similar to purple starthistle; mature seed heads are necessary for positive identification. Iberian seeds have a plume of several bristles, while purple seeds do not. Iberian flowers tend to be lighter purple and the heads are generally more globular.Habitat
Grasslands; purple is more abundant on fertile sites, while Iberian favors streambanks and wet areas.Distribution
Clackamas County, Oregon; isolated populations in WashingtonImpacts
Displace valuable forage and native species, spines deter grazing animals, reduce value of hay, impede recreationDispersal Methods
Vehicles, harvest machinery, humans, animalsPrevention
Look for these species in waste sites, moist, grazed areas, uncultivated fields, and along traffic corridors such as roadsides and cattle trails. Check hay, seed equipment and livestock for seeds. Seeds stick easily to clothing, fur, and machinery; take heed in cleaning off such after being in an infested area. Take prompt action with small infestations.Listings
ODA's A ListFactsheets
Washington State University Cooperative Extension Fact Sheet
Photos
Photos of Iberian Starthistle
Distribution Map
Distribution of Purple Starthistle in Washington
Distribution of Iberian Starthistle in Oregon
Distribution of Iberian Starthistle in Washington
Other Links
Species Profile for Purple Starthistle from the Oregon Department of Agriculture's Noxious Weed Control Program
Integrated Vegetative Management for Purple Starthistle
Managing Purple and Iberian Starthistle