|The belladonna species are long-lived, sturdy, bushy perennials. Leaves are deeply cut and stems are short. All delphiniums are easy to grow from seed, sown in pots or flats in late July or August. Transplants should be set out in October for late spring to early summer bloom. In colder areas, sow seeds from March to April or set out transplants from June to July for September bloom. Rich, well-drained soil is a must for delphiniums and they love regular fertilizings. Delphiniums will not do well in strongly acid soils, so add lime to make soil more neutral. A little superphosphate worked into hole when planting will result in a stronger plant. Do not cover root crown and beware: Snails and Slugs LOVE this plant, so keep area clean and free of debris.
In spring, remove all shoots, except for 2 or 3, and side dress plants with a complete fertilizer. Stake plants early and remove old flower spikes immediately after bloom, leaving only foliage. Once new shoots are several inches tall, cut old stalks back hard. If plants have been well fertilized, you should get a second flush of flowers for fall.