Intense eradication programs have eliminated most populations in the state. Often found growing in cattle manure from seed passed through digestive tract. Seedling shoots grow slowly compared to its roots and to shoots of alfalfa and some clovers. Deciduous in cool climates. Morphology is variable depending on environmental conditions.
Thorns are smaller and fewer, and leaves larger and more numerous in moister habitats.
Rhizomes at depths to 1.5 m produce new shoots and deep vertical roots at about 1-1.5 m intervals. In turn, each new clone sends out rhizomes in all directions. Infestations can spread at a rate of about 10 m per year. Sepals persistent, fused and cup-like, with small unequal teeth . Stamens 10, with bases of 9 filaments fused into a tube around the style and 1 separate.