Crocanthemum canadense aka Canada Frostweed

Crocanthemum canadense is in the rockrose family, Cistaceae. People call it frostweed and longbranch frostweed. The supplied garden sources use the name Helianthemum canadense. Its native range spans eastern Canada and much of the eastern United States. Kew also lists the north-central United States and northern Mexico. In Mexico, it grows in Sonora and Chihuahua. It grows in temperate regions. It is not native to Britain or Ireland.

Kew calls this plant a subshrub, or small shrub. Plants For A Future calls it a perennial. It grows to about 1.3 feet (0.4 metres) tall. In the wild, it grows in open woods, clearings, and barrens. These sites often have dry, sandy soil. A sunny woodland edge suits it in a garden. The evidence gives no width for a full-grown plant. Nor does it describe the leaves in detail.

Plants For A Future gives May to July as bloom time. Each flower has both male and female organs. Insects pollinate the flowers. The plant also uses cleistogamy: some flowers pollinate themselves while shut. The supplied species sources give no flower colour or fruit details. The RHS page describes flower shape for the genus alone. This does not show what this species looks like.

Grow frostweed in an open site with full sun. It will not grow in shade. Use light sandy soil or medium loam that drains well. The soil can be dry or moist. The stated pH range is 5.5 to 8. Plants For A Future lists USDA zones 6–9. Sow seeds in a greenhouse in spring. When seedlings are large enough to handle, give each its own pot. Keep them under glass for their first winter. Plant them out after the last expected frost. You can also grow new plants from late-summer cuttings. Take these from wood that is firm in part.

Plants For A Future lists no known food uses. It notes past use of dried leaves and leaf tea as medicine. People used these for sore throats, kidney complaints, and skin problems. These records do not prove that the treatments work. The same source warns that too much can cause nausea and vomiting. Yet its general hazard entry lists no known hazards. Read these claims with care. It lists no other uses. It does not flag a risk of becoming a weed.