Delphinium Pacific Giant King Arthur has brilliant royal violet flowers with white bee. Plants form a low mound of deeply-cut green leaves, bearing tall spikes of satiny flowers. Removing faded spikes at the base will encourage repeat blooming in fall. In hot, humid summer regions, plants do not usually last more than 2 to 3 years. Stake plants when planting. Do not leave it for another day. That is not an option. The gardener that ignores this step will be heartbroken. The stems of the Delphinium will be broken, as well.
Staking is necessary on a windy site and with larger varieties. It is best to start when plants are still small and use a square or triangle of 120cm (4ft) canes close to the plant and tied together with twine. Place the canes 30cm (1ft) in the ground taking care not to damage the crown or the roots of the plant. This allows the spikes some movement. Twigs can also be used successfully and are less obtrusive. Start tying the plant at about 15cm (6in) with the final tie just below the florets. Tie firmly but not too tightly and always allow the plant some movement so that spikes do not snap in the wind.Blooming is consistent throughout the summer from June to September, the sturdy flower spikes are very attractive to bees and make a wonderful cut flower .Height 54-72 inches with a spread of 18-23 inches, Zones 3a-7b. Especially attractive with foxglove, tall bearded iris and peony. Fertilize well and stake if desired. Cut back after flowering for rebloom. Plants are often attacked by mildew in mid summer; simply cut back hard to encourage fresh foliage. Use a high phosphorous fertilizer each year, in early spring. CAUTION: Harmful if eaten. Attracts Butterfly and Hummingbirds
How to Grow Delphinium From Seeds
Use a good, loose potting soil, firming it down into flats or pots with a wooden block and then moisten before sowing the seed
Cover seeds about 1/8 Of an inch by sifting soil over them. Keep moist and shaded until seeds germinate, then remove shadeing.
August sown seed produces seedlings that can be wintered over in a cold frame and given a permanent place in the garden the following spring. Plant delphinium seeds in early August for bloom next midsummer. Seeds germinate best when fresh.
The trick in hot-weather sowing is to keep the seed box dark and cool until germination, and then gradually to admit light and air. Keep soil moist but never wet. When three true leaves show, transplant to a shaded coldframe for winter. Approx. finish: 18 weeks