Cirsium arvense (L.) Scop.
Creeping Thistle, Canada Thistle, Canadian Thistle, Lettuce from Hell Thistle, California Thistle, Corn Thistle, Cursed Thistle, Field Thistle, Green Thistle, Hard Thistle, Perennial Thistle, Prickly Thistle, Small-flowered Thistle, Way Thistle, Stinger Needles
Cirsium arvense subsp. arvense, Cirsium arvense var. arvense, Breea arvensis, Breea dioica, Breea ochrolepidia, Breea praealta, Breea setosa, Carduus arvensis, Carduus haemorrhoidalis, Carduus neglectus, Carduus segetum, Carduus serratuloides, Carduus setosus, Cephalonoplos arvense, Cephalonoplos arvensis, Cephalonoplos ochrolepidium, Cephalonoplos segetum, Cephalonoplos setosus, Cirsium albicans, Cirsium albiflorum, Cirsium argenteum, Cirsium argunense, Cirsium x celakovskianum, Cirsium dioicum, Cirsium halophilum, Cirsium horridum, Cirsium incanum, Cirsium laevigatum, Cirsium macrostylon, Cirsium mutatum, Cirsium neglectum, Cirsium ochrolepidium, Cirsium praealtum, Cirsium ruthenicum, Cirsium setosum, Cirsium sordidum, Cirsium stocksii, Cnicus arvensis, Cnicus candicans, Cnicus lanatus, Cnicus macrostylus, Cnicus neglectus, Cnicus ruthenicus, Cnicus setosus, Cynara repens, Serratula arvensis, Serratula incana, Serratula setosa
Color: Purple to white
Bloom Time: Late June to August
Cirsium arvense is an erect, perennial herbaceous plant, up to 4 feet (1.2 m) tall with an extensive creeping rootstock and ridged and hairy stems. The leaves are lance-shaped, irregularly lobed, up to 6 inches (15 cm) long with weakly to strongly prickled margins. The flowers are purple to white, up to 1 inch (2.5 cm) long and 0.5 inch (1.3 cm) across. Flowering occurs in late June to August. The seeds are called achenes, up to 1.5 inches (3.8 cm) long and have a feathery pappus.
How to Grow and Care
The seeds of Cirsium can be sown in either autumn or after the last frost of spring. They should be sown at a depth of 0.12 inches (3 mm). If grown indoors first, then Cirsium takes about 2 to 3 weeks to germinate at a temperature of 70 to 75 degrees Fahrenheit (21 to 24 degrees Celsius). The seedlings should be planted out in early spring when it is still possible to get a frost with a spacing of about 2 feet (60 cm).
Cirsium thrives in full sun and poor, average, or reach soil that is moist but well-drained. Plants require little care, but deadheading limits their tendency to self-sow. They generally self-sow only in moderation, and unlike weedy thistles, the seedlings are easy to pull up. Use Thistles in mixed beds, herb gardens, or meadow-like plantings. See more at How to Grow and Care for Thistles (Cirsium).