Fruit of the marginal flowers dark colored and without bristles, inner fruits lighter in color with a terminal tuft of white-silvery bristles. Yellow starthistle is a bushy annual or sometimes biennial. It is covered with loose white cottony wool. It spreads by seeds that can remain dormant for 10 years. Seedflies and weevils are being used, but an effective control is many years away.
Cultivation effectively controls yellow starthistle.
Repeated cultivation is required to control each new seed flush. Repeated mowing can also be effective, if properly timed. Waiting until the early flowering stage leads to less regrowth. Contact you local weed board for information about the ongoing war against this invasive pest.