Common Tansy
A perennial herb that forms dense colonies through both seed dispersal and creeping rhizomes. It has a tall, upright growth habit, often forming large clumps of erect stems topped with yellow flowers. In situ, common tansy appears as a large, bushy mass with clusters...
Blueweed
Blueweed is native to Southern Europe and West-Central Asia. It escaped from cultivation in North America as an ornamental and is now widely distributed throughout.
Common Burdock
Common burdock is not considered a problem in crops since it is intolerant to cultivation. Livestock are fond of common burdock, and the foliage imparts a bitter taste to the milk if it is eaten in large quantities.
Bull Thistle
Bull thistle is often a transient species, appearing in recent clear-cuts or disturbed areas and becoming a dominant species for several years