Cirsium hookerianum aka White Thistle

Cirsium hookerianum is a thistle known as white thistle. It belongs to Asteraceae, the daisy family. Its native range runs from western Canada into the northwestern United States. It grows in moist low ground and on open, rocky slopes. Records also place it in fields used for crops. It thus grows in both wild sites and worked ground.

This short-lived perennial reaches about 5 feet [1.5 metres] tall. It lives for more than one growing season, but not long. The source gives no spread or full account of its leaves. It gives no details of stems, flower colour, or fruit. Each flower has both male and female organs. Bees, flies, and beetles help pollinate the plant. Moths and butterflies do so too. It is self-fertile and can set seed with its own pollen. The source gives no months when it blooms.

Plants For A Future says it prefers moist soil. It states that the plant cannot grow in shade. Listed soil types include sand, loam, and clay. The stated pH range runs from mildly acid to mildly alkaline. The account places it in garden beds and wild sites. Its wider garden advice draws on the needs of the genus. This does not count as tested care for this species. The source is unsure how well it withstands British cold. Its native range suggests it might grow outdoors there. Yet this gives no firm hardiness rating.

The root has a recorded food use once cooked. It can serve as a boiled vegetable or go into soups and stews. You can dry the root to store for later use. The source suggests that it may contain much inulin. People cannot digest inulin, and it can cause gas as it ferments. Plants For A Future rates its food value two out of five. It lists no known use as medicine and no known hazards. This last claim does not prove safety for people or pets.

The source records seed as the way to raise new plants. It advises sowing outdoors in early spring or autumn. It states that seeds sprout in two to eight weeks at 20°C. The evidence gives no pest or disease details for this species. The insects that visit it link it with garden wildlife. The evidence does not show other uses in the landscape.