BMNRI Home > Publications
> Weeds > Musk Thistle
Publications: Noxious Weeds
in Slow Motion: A
talk by Jerry Asher about noxious weeds in the Blue Mountains
Click on a weed to learn about how to find it and kill it!
- Leaves: Up to 10 inches long, dark green with a light
green midrib, and spiny.
- Flowers: Large, solitary, purple or deep rose, occasionally
white, and nodding. Outer bracts are flat and spreading, ending
in spines; inner bracts are narrow and softer. Flowering period
starts in June.
- Seeds: 3/16-inch long shiny yellowish-brown and with
a hair-like plume.
Musk thistle is a biennial plant that infests pastures, rangeland,
and timberlands, and also roadsides, waste areas, ditch banks, and
stream courses. It aggressively forms dense stands, crowding out
native species. It spreads by seed.
- Chemical: Herbicides are effective. Call your local weed
control office for the latest methods of eradicating this noxious
- Biological: An introduced seedhead weevil feeds on the
seeds and limits spread.
- Mechanical: Maintenance of fields and range through fertilization
and irrigation helps prevent infestation. Cutting off the rosette
below the crown kills the plant, and mowing in bud season can
reduce seed production. Burning is *not* advised as it kills the
Report all sightings to your local