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Key identifying traits
Large, 1 ½ -3" diameter bent over (nodding) flower
heads
Flowers are rose, violet or purple and one per stem
Bracts surrounding flowers are broad and spine tipped
Upper flower stems typically bare and lower stems are
winged with spines
Leaves are dark green, lobed and spiny with light green
midrib
Older plants are multi-branched & grow to over 6'
tall
Biology and ecology
Biennial or sometimes a winter annual
Invades pasture, range ,forest, road sides and fields
Reproduction of musk thistle is entirely by seed
Numerous small roots in the fall; large fleshy taproot
in spring
Only 2% of seeds have pappus and are wind borne
Can form dense stands, discouraging animal presence and
forage
Native to Europe & Asia
Control
Prevention- Learn
to identify the plant; know your property; beware of fill dirt, hay,
manure and seed from outside your area
Biological – Biological
controls well established in all parts of the county and dramatically
reducing musk thistle stand density and vigor
Cultural – Competitive
vegetation helps reduce open spaces for invasion
Mechanical – Mowing,
cutting, digging, pulling or cultivation are all effective if done prior
to flowering and repeated if necessary; seed bank will be present for
years
Chemical – Several effective
at label rates; best timing is when plants are in rosette stage or early
bolt-spring and again in fall;
refer to the
PNW Weed Management Handbook for specific chemical recommendations |
mature plant
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