The most popular varieties belong to the Elatum group which have D. elatum as the parent species. These plants have the classical Delphinium shape and flower form with upright spikes bearing large flat flowers which may be semi-double or doube. They attain a height of four to five feet.
The tall ones grow to six feet and include 'Gordon Forsysth' (blue), 'Bruce' (purple), 'Fanfare' (mauve), 'Faust' (blue), 'Michael Ayres' (purple) and 'Nimrod' (purple).
The medium varieties are numerous, look for 'Blue Nile' (blue), 'Royal Flush' (pink), 'Sungleam' (pale yellow), 'Min' (pale purple), 'Spindrift' (blue/lilac) and 'Turkish Delight' (pink/mauve).
The dwarfs grow three to four feet high and examples are 'Lord Butler' (blue), 'Tiddles' (mauve) and 'Mighty Atom' (blue).
The second major section is the Belladonna group which attains a height of three to four feet with slender stems and branching flowerheads that are cupped not flat. The blooms are small and wide spreading. Popular varieties include 'Pink Sensation', 'Casa Blanca' and 'Blue Bees'.
The third section is the Pacific group. They are tall, large flowered plants which are grown from seeds as annuals or biennials. Look for 'Galahad' (white), 'King Arthur' (purple) and 'Guinevere' (pale purple).
Delphiniums require well drained fertile soil and thrive best in a sunny and sheltered site. To propagate divide clumps in spring. With Pacific Delphiniums sow seeds in March in gentle heat and plant out in May.