Biennial & Perennial Weeds
THISTLE: BULL, MUSK, PLUMELESS Cirsium vulgare, Carduus nutans and Carduus acanthoides Life Cycle: Biennial Plant Description: Bull Thistle: Erect, 2 to 5 feet tall with many spreading branches, spiny wings from leaves. Rosette forms first year; flowering stem elongates second year. Leaves have short prickles on the
surface and are cottony below. Flowers are dark purple and somewhat clustered. Musk Thistle: Erect, freely branching, up to 7 feet tall. Leaves are dark green with light midrib, hairless on both sides, with long, sharp spines. Flowers are deep rose to purple, up to 3 inches in diameter. Plumeless Thistle: Branching plant with spiny wings that extend up to flowers. Stems grow 1 to 4 feet tall. Rarely flowers the first year. Flowers are purple to pink, 1 to 2 inches in diameter, solitary or in clusters of two to five. Bracts are sparsely to densely hairy.
Treatment: Apply 16 fluid ounces of HighNoon ® herbicide per acre during the rosette stage early in the season. Fall to early winter applications can be made to rosettes prior to the first hard frost.
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