This species has been in North Dakota for many years and infests about 3,500 acres. It's a perennial with black, spreading roots that form new shoots. Its growth characteristics are similar to those of Canada thistle. It's the only one of the three species that causes significant crop losses. It can be identified by the rounded bracts with transparent tips at the base of pink to lavender flowers.
Largest infestations are in southwestern North Dakota.
This species is a short-lived perennial or biennial with a taproot. The plant infests about 1,500 acres in North Dakota. Infestations may remain in a confined location for several years then spread rapidly. It's important to control the weed as soon as it's identified and monitor the location for regrowth. This is also a short-lived perennial or biennial with a taproot.