Delphinium brachycentrum aka Northern Larkspur

Delphinium brachycentrum, or northern larkspur, belongs to the buttercup family, Ranunculaceae. Its native range spans the Russian Far East and western subarctic America. It grows in subalpine and subarctic climates. In Alaska and the Yukon, it lives on well-drained tundra slopes. These sites range from sea level to 5,250 feet [1,600 metres]. It is not native to Britain or Ireland. The RHS lists Delphinium chamissonis as a synonym.

This perennial reaches about 3.3 feet [1 metre] tall and wide. It flowers from July to August. Each flower has both male and female organs. PFAF describes it as an ornamental plant for garden beds. In the wild, it crosses with Delphinium glaucum. That cross produces the hybrid Delphinium × nutans. The supplied species accounts give no details of flower colour or fruit. They also give no species-level account of leaf shape.

Grow northern larkspur in an open site with full sun. It does not grow in shade. It prefers rich soil that stays moist but drains well. Avoid ground that holds standing water. Sandy, loamy and clay soils can all suit it. It accepts mildly acid, neutral and mildly alkaline conditions. PFAF lists USDA hardiness zones 4–8. It also warns that this plant can hinder nearby plants. Legumes may suffer more than other neighbours. PFAF does not flag it as weedy.

Seed, division and basal shoot cuttings offer ways to raise plants. Sow seed in a cold frame during March or April. Outdoor sowing is an option in May. Keep the seed moist and shaded until it sprouts. At 59°F [15°C], germination can take two to nine weeks. Higher temperatures can inhibit germination. Seed does not stay viable for long. PFAF recommends sealed storage at about 37°F [3°C]. Move seedlings into separate pots once large enough to handle. Plant them in their final sites during summer. Divide plants in spring or early autumn. Take basal shoot cuttings in April or May, before their bases become hollow.

All parts are poisonous, with young growth posing the greatest risk. PFAF records no known food uses or medicinal uses. The leaves have supplied a substance used against parasites. This use carries a toxicity warning and is external only. It does not make the plant safe to eat.