Field Guide to Noxious and Other Selected Weeds of British Columbia
Bull Thistle (Cirsium vulgare)
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- taprooted biennial with spiny winged stems growing 0.3 to 1.5 metres tall; leaves end in long, sharp spines; upper surface with short prickles, undersurface cottony; flowerhead bracts tipped with prickles; purple flowers 4 to 7.5 cm across
- often confused with Canada thistle (Cirsium arvense) which has creeping roots, much smaller flowers and weak prickles, not spines on the leaves
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 | Stiff spines at leaf tips
Photo courtesy BC Ministry of Forests
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 | Spine-tipped flowerhead bracts |
More information on bull thistle (Weeds BC)
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