Unusually for a thistle,
Cirsium heterophyllum lacks spines. Growing tall, the plant forms creeping
stolons (runners). The stem is grooved but unwinged, more-or-less branchless, and cottony. The leaves are green and hairless above, thick white-felted underneath. The basal leaves are
lanceolate with
petioles and softly prickly edges, and grow long, and wide. The upper leaves do not have
petioles, clasping the stem with
cordate (heart-shaped) bases. The
flower heads are 3 to 5 cm long and wide, the flowers red-purple, appearing from July to August. ==Distribution==