elatum, chinesnis, grandiflorum, hybrids
Perennial, often treated as biennial in warm climates.
Transplant within 2 weeks of arrival or bump up into a larger cell until you can transplant.
|Netting / Staking||
Varies by location. Delphinium will need staking if grown in high wind and/or heavy rain locations.
-35 to 75F
6-12". 18" in cool summer locations.
Fertile, moisture retentive soil.
Facultative long day.
|When to Plant||
In hot summer locations, plant 2-4 weeks before first frost for bloom the following spring. Can also be planted in a cool greenhouse in winter for spring flower, as you would grow snapdragons. In cool summer locations, plant any time and establish as a true perennial.
Harvest when 1/3 of florets are open. Cut to the ground to encourage regrowth.
|Post Harvest Care||
Use a holding solution. Delphinium is highly sensitive to ethylene and treatment should be considered.
|Diseases / Insects||
Powdery mildew should be managed at first sign of infection. Belladonna types seem to be more susceptible to mildew. Broad mites and cylclamen mites can cause puckering of the foliage and distortion of the flowers. Manage with predatory mites.
The only thing to know is that Delphinium hate heat. If you live in a hot summer location, you need to plant in the fall or late winter and grow them like a hardy annual. In locations with cool summers they become long lived perennials. Cut back to the ground when you harvest and they will often regrow and rebloom. When established as long-lived perennials, thin the new growth to 3-5 shoots per plant to produce better quality flowers.
|Resources||National Garden Bureau Delphiniums, a perennial favorite|
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