Bull Thistle

cirsium vulgare, is a eurasia native that invasives disturbed areas in the u.s. it grows up to 7 ft tall.

from http://montana.plant-life.org

edible uses:
the root of bull thistle is edible cooked. it has a taste somewhat like a jerusalem artichoke, but not as nice. a rather bland flavor.
young flower stems can be cooked and used as a vegetable. the flower buds can be cooked and used like globe artichokes, but they are smaller. the dried flowers has been a rennet substitute for curdling plant milks. the seeds has occasionally been eaten roasted.

medicinal uses:
a hot infusion of the whole plant has been used as a herbal steam for treating rheumatic joints. bleeding piles have been treated by a decoction of the whole plant, used both internally and externally.