Bull Thistle is a broadleaf weed commonly found in Iowa lawns. There are many varieties of thistle found in the United States. This thistle is a biennial weed that grows during the summer. The foliage of the Thistle is pointed and form in a rosette. The foliage has toothed margins. The foliage of the thistle is ordained with cactus like spikes. These spikes cover the entire surface of the foliage. This biennial weed forms a tap-root the first year. In the second year, the thistle forms a fibrous root system. This weed produces stems that display flowers. The flowers of this thistle are pink to purple in color. This weed flowers in June through October. The thistle spreads by seed.
Treat this plant with a selective broadleaf herbicide when the plant is actively growing.
Similar broadleaf weeds.
- Canadian Thistle
- Spiny Sowthistle
- Yellow Thistle