Bull thistle
Cirsium vulgare (Savi) Tenore

Bull thistle is the least serious of the introduced thistles in North Dakota, and generally is found in the northern and eastern counties of the state. Bull thistle is a biennial and grows from a flat rosette of leaves the first year to a flowering stem up to 5 feet tall the second.

Bull thistle heads are usually found singularly at the end of each stem branch. The flowers are gumdrop shaped, large (usually 2 or 3 inches tall), with long, stiff, yellow-tipped spines.

The achenes are 0.1 to 0.15 inches long, glossy light brown to pale yellow or white with narrow dark brown stripes.

Although the seed readily germinate, survival is low, and the plant is often found growing singularly or only scattered in pastures and wooded areas. Distinguishing characteristics of bull thistle are the leaves and the broad prickly wings that line the stem.

Leaf margins are deeply toothed, and toothed again (double dentate) with prominent stiff spines. The leaves have prickly hairs above, especially along the midvein, and are cottony below. The stems are very pubescent with dark purple veins. The plant appears bushy rather than the candelabra appearance of plumeless or Canada thistle.

The rosette leaves of bull thistle are deeply lobed and very pubescent with dark purple ribs. Native Americans used bull thistle to treat hemorrhoids, which they likely learned from French fur trappers. Bull thistle is often the thistle species referred to as an edible plant. Many parts are edible from the root to the flower. The petals were used as chewing gum or tobacco by Native Americans.