Delphinium

March 20, 2023

Life Cycle	Perennial, sometimes treated as biennial in warm climates.
Zone 5 Treatment	Can plant 4-6 weeks before last frost for a first year bloom, otherwise you may or may not get a first year bloom. Cover over the winter and they will come back in early spring and also re-seed themselves.
Seedling Care	Transplant within 2 weeks of receiving otherwise the roots can get too crowded and harm the overall health of the plant.
Netting / Staking	Delphinium will need staking if you are growing in a location with high winds or heavy rains
Temperature Range They Will Tolerate	-35 to 75F
Spacing/Height	6-12″ spacing. 18″ in cool summer locations.36”-48” height
Soil Preference	moisture retentive soil. Per usual, compost and spend time on soil health before planting
How to cut for maximum blooms	Make the first cut from the central stem, 2-3 inches above ground level. More shoots will continue to mature and develop after the central stem is harvested. Cut all future stems the same. For longest lasting flowers, cut when the bottom 1/3 of the flowers on a stem are open.
Pinching	No
When to Plant if you are NOT in Zone 5	In hot summer locations, plant 4-6 weeks before first frost for blooms the same spring. Can also be planted in a cool greenhouse in winter for spring flowers. In cool summer locations, plant any time and establish as a true perennial.
Post Harvest Care	Room temp water with flower food. Delphinium is highly sensitive to ethylene, therefore DO NOT store them in a cooler with any fruits or vegetables. Take off all of the leaves and foliage. Leaves and foliage of any cut flower should never be submerged underwater because they decay quickly in water and cause a fast build up of bacteria.
Diseases / Insects	Powdery mildew should be managed at first sign of infection. Belladonna types seem to be more susceptible to mildew. We grow completely organically and also encourage you to also. TO treat powdery mildew organically, see this resource:https://www.growingagreenerworld.com/controlling-or-eliminating-powdery-mildew/ Broad mites can cause puckering of the foliage and distortion of the flowers. You can try to manage them with predatory mites or neem oil.
Sweet Pea’s Notes	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.
Vase Life	7-14 days