Delphinium caeruleum

Delphinium caeruleum is a perennial in the buttercup family, Ranunculaceae. Its native range runs from Qinghai through the Himalaya and central China. It grows in temperate regions and is not native to Britain or Ireland. In the wild, it occurs in alpine sites. These lie at about 8,200–16,400 feet [2,500–5,000 metres] above sea level.

This small plant reaches about 1 foot [0.3 metres] tall. Its spread is also about 1 foot [0.3 metres]. It flowers from July to August, with seeds ripening during those months. Each flower has both male and female organs. The supplied species account gives no details of flower colour or leaf shape. It lists cultivated beds as a place to grow the plant.

Give it an open site in full sun. It needs rich soil that drains well but stays moist through summer. Sandy, loamy and clay soils fall within its stated range. Yet heavy ground can cause plants to die during winter. Avoid sites where water collects and the soil stays waterlogged. It accepts mildly acid, neutral and mildly alkaline soil. Plants For A Future lists USDA zones 6–9. The same source warns that it can check nearby plants' growth. Legumes may be more affected than other neighbours.

Seed, division and basal cuttings offer ways to raise new plants. Sow seed in a cold frame in March or April. Outdoor sowing can follow in May. Keep the seed moist and shaded until it sprouts. At 59°F [15°C], germination takes about two to nine weeks. Higher temperatures can hinder this process. Seed loses viability, so sealed storage at about 37°F [3°C] is advised. Move seedlings into separate pots once large enough to handle. Plant them in their final sites during summer. Take basal cuttings in April or May, before their bases become hollow. Divide plants in spring or early autumn.

All parts are poisonous, and young growth poses the greatest risk. No edible uses are recorded. Leaves and roots have supplied substances used to kill parasites. One recorded use involved killing maggots in goats' wounds with roots. These records describe past uses, not safe home treatments. The source restricts such uses to external application because of toxicity. It records no weed potential for this species.