Cirsium spp. Mill.

Asteraceae (Sunflower Family)


Ten species of thistles are found in Texas. One of the more common species, Texas thistle (C. texanum), is a prickly, tap-rooted biennial that reaches 2 to 5 feet or 0.6 to 1.5 m tall. Each plant begins growth as a rosette, or a circular cluster of leaves, during the winter and sends up a flowering stalk in the spring. The leaves are extremely spiny and located alternately along the stems. In some species, the leaf bottom may be woolly with small hairs. Showy purple flowers occur in late spring and summer and mature into a white plume. The seeds scatter profusely in the wind. Although the forage value of thistles is poor for livestock and wildlife, seed-eating birds feed on the seeds of many thistles. Thistles also supply nectar for some butterfly species, and flowers are worked by bumblebees when they mature.


Thistles are common in dry or moist soils throughout Texas. They thrive in disturbed or overgrazed areas, prairies, abandoned fields, and along roadsides.