Part of the Pacific Giants Hybrid group of Delphiniums, 'Black Knight' features deep purple blue semi double flowers, each with a dark eye, on stout stems, and can form an invaluable part of the larger perennial border, being of impressive stature when mature. Reaching heights of up to 1.75 metres and spreading to over half a metre, this plant makes a bold statement. Loved by pollinators, it's airy plumes of richly coloured flowers appear in May and June. If cut back to a flowering side shoot after they have faded a second flush can often be achieved. Will require staking, especially in windier situations, and delphiniums are a favourite for slugs and snails, so protection is required in spring when the new shoots are emerging. Such a small amount of effort though for such an abundant display of flower power. Happy in full sun or semi shaded conditions in any reasonably rich and moist but well drained soil.