Stem
- To 5 ft. tall; forms basil rosette, then rapid growth forms flower stems; lower parts of flowering stems are winged
Leaves
- Fuzzy leaves with deep, rounded lobes; leaves decrease in size higher on the plant
Flower
- White to pink to purple petals, 0.5 in. tall and 0.5 in. wide with fuzzy hairs at their base; flowers often appear to have no petals; bracts at the base of the flower have light brown, pointed spines; seeds are tiny, barrel-shaped and have a crown of fine hairs that aid in wind dispersal
Root
- Stout, deep taproot and many fine, water-absorbing, surface roots
Other
- Grows best on disturbed ground and seasonally flooded sites; no known occurrences in Nevada
- Winter annual; each plant can produce several thousand seeds; seed remains viable in soil for several years
- Can outcompete native vegetation by rapid growth which shades out other plants
Control
- Mechanical removal by pulling, digging or hoeing is effective; if plant is flowering, bag up plant and dispose of properly
- Apply aminocyclopyrachlor+chlorsulfuron, aminopyralid or clopyralid preemergence or post emergence in the seedling to rosette stage; apply 2,4-D or dicamba post emergence during rosette to early bolting stage
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B.
2020,
Nevada Noxious Weed Field Guide – Mediterranean desert knapweed,
Extension, University of Nevada, Reno, Field Guide
