Delphinium

Delphinium elatum

Delphiniums produce the most magnificent blue flower spikes in the herbaceous border — a colour intensity that no other garden plant can match. The tall, stately spikes of 'Pacific Giant' and 'New Millennium' hybrids can reach 1.5 metres, creating a breathtaking display in June and July. They need staking — insert supports when plants are 30cm tall, before the heavy spikes develop. After the first flush of flowers, cut stems down to emerging side shoots for a smaller second flowering in September. Delphiniums are perennial but can be short-lived, especially in heavy, waterlogged soil. They prefer rich, well-drained, alkaline soil and a sheltered position — strong winds shred the tall flower spikes. Young shoots are irresistible to slugs, which can destroy the emerging growth in spring; protect diligently. Seed-raised delphiniums vary in colour; for guaranteed colours, buy named varieties as plants or take basal cuttings in spring from established clumps.

Plan where to grow Delphinium using our vegetable garden planner.