Scotch Thistle
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Scotch Thistle
Asteraceae (Sunflower Family)
Class A Weed
Description: Scotch thistle is an aggressive biennial
that reaches a height of 12 feet at maturity. Stems
have broad, spiny wings formed by leaf bases.
Leaves are large and spiny. Rosette leaves are large (up to
2 feet long and 1 foot wide), spiny, and covered with a dense mat
of hairs that give the plant a grey color. Stem leaves are hairy, alternate, and coarsely
lobed. Violet to reddish flowers look like a shaving brush up to 2 inches
in diameter. Spiny bracts surround the flower head.
Origin: Europe
Key Characteristics:
- Large, hairy rosettes
- Winged stems
- Large size and gray color of the mature plant
Distribution:Isolated populations of Scotch thistle have
been identified in the state. The potential for spread is not as great as with
other thistles (namely musk thistle), but its potential impact is just as great.
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