Biennial thistle seed generally germinates in the summer and fall, and the plant overwinters as a rosette. The following spring, the plant resumes vegetative growth, bolts and flowers. ... Occasionally biennial thistles have winter annual, annual or short-lived perennial characteristics.

Do thistles grow back?

Thistles are perennial weeds that grow back year after year forming deeper and deeper roots as it establishes itself. They don't tolerate mowing well though and this on its own can be enough to get rid of them.

Is thistle an annual or perennial?

All thistles addressed in this guide are annual to biennial in growth form. They reproduce solely by seed and are prolific seed producers. The seed remains viable in the soil for many years. At maturity, these spiny weeds have basal rosettes, purplish disk flowers, and flowering stems that are highly branched.