Swamp Thistle is showy when it blooms and has large, dried flower heads when it dies.
A native biennial in the Cirsium genus, swamp thistle stands five to ten feet tall and produces 1″ long purple flowers on hollow, spineless stems. When the plant flowers in mid to late summer it’s in its second year, so by the time you find its dried flower heads in winter the plant is dead.
Look for swamp thistle in swamps, wet woods and thickets. On the ground nearby you’ll see its first year plants overwintering as flat rosettes of prickly leaves.
My Weeds in Winter book says you can easily find these rosettes if you walk barefoot in the vicinity of the flowering plant.
Yow! Not a good idea!
(photo by Dianne Machesney)
It was some other species of thistle that grew in our yard when I was a kid – I remember having a strong dislike for them due to the spiny thorns.