Above: Bull Thistle along shore of Lake Wingra in Vilas Park with spiny tipped bracts (8/24/22).
Bull Thistle - Cirsium vulgare (Introduced - naturalized; ecologically invasive)
Bull Thistle can grow anywhere from 2 - 6 feet in height.
Bull Thistle is a biennial plant. Biennial means that it takes two seasons to complete their life cycle The first season they germinate and create a rosette. The second season they flower and produce seeds. Bull Thistle only reproduces by seeds.
Bull thistle has pink/purple flower that are about 1 1/2" wide
The Bull Thistle (Cirsium vulgare) is Scotland's national flower. Folklore has it that in the mid 13th century during a surprise nighttime invasion, the thistle helped defeat invading Norsemen when the Norse soldiers (who had taken off their shoes to be stealth) stepped on the spiky plant in their bare feet. Their screams of agony awoke the sleeping Scottish clansmen who then thwarted the invaders.
There is debate as to whether it was the Bull Thistle (that is native to Scotland) or the Cotton Thistle (Onopordum Acanthium) that is also called the Scotch Thistle (but is not native to Scotland).
Blooms: June - October
Other names include: Common thistle, Spear thistle.
Etymology: vulgare – Latin for common
Above: Bull Thistle spine-tipped leaf in field near the Westside Community Farmer's Market on University Row in Madison, Wisconsin on July 30, 2022
Above: Bull Thistle stalks covered with leafy, spine-tipped “wings” in Madison, Wisconsin (left: on 8/13/22 in Wingra Park and right: on 8/2/22 in field near the Westside Community Farmer's Market on University Row in Madison, Wisconsin.
For more information on the Bull Thistle (Cirsium vulgare), visit Wikipedia.
Or, visit the UW-Madison Wisconsin State Herbarium website page about Bull Thistle - (Cirsium vulgare) .
Or, download a pdf about Bull Thistle from the University of Wisconsin Extension's 2017 Weed Identification Series
Or, to compare it other Biennial thistles (Musk and Plumeless) download a Biennial Thistle Comparison pdf from the University of Wisconsin Extension's 2017 Weed Identification Series/Biennial Thistle Comparisons
Bull Thistle
Cirsium vulgare
Above: Bull Thistle in in woods near Marion Dunn Pond and Oak Savanna in Madison, Wisconsin on August 21, 2019.
Above: Bull Thistle stalk and leaves growing in field near the Westside Community Farmer's Market on University Row in Madison, Wisconsin on July 30, 2022.
Above: Bull Thistle in Wingra Park on August 13, 2022.
Above: Bull Thistle on shore of Lake Wingra in Vilas Park on August 15, 2022.
Above: Bull Thistle stalk and leaves growing in field near the Westside Community Farmer's Market on University Row in Madison, Wisconsin on August 2, 2022.
Above: 1913 Bull Thistle (Cirsium vulgare) line drawing.
Above: Bull Thistle (Cirsium vulgare) botanical illustration cicra 1796.
Above: Bull Thistle specimen collected in La Crosse County, Wisconsin on August 24, 1977.
Above: Video on how to identify Bull Thistle from the University of Idaho College of Agriculture.