Hardiness zones
Sunset All
USDA All
Landscape Use: Mixed flower borders, accent, containers
Form & Character: Strongly erect, stiff, formal, fern- like
Growth Habit: Moderate depending on cultivar from 1 to 4' tall, usually narrow with few lateral branches.
Foliage/Texture: Lower basal foliage have long petioles, yet upper foliage is sessile, 3 cleft and highly, linearly segmented, usually light green; fine texture.
Flowers & Fruits: 4-16 blooms set densely on terminal spike, mostly blue, some pink, white and violet, sepals about 5/8" long with slender spur; fruit inconspicuous.
Seasonal Color: In Phoenix, delphiniums bloom in early to mid spring.
Temperature: Delphiniums are intolerant of freezing conditions, but thrive during times of cooler weather when daytime highs are below 90oF. Cultivation in Phoenix is during fall, winter and spring. Summertimes are just too hot.
Light: Full sun to partial shade is best.
Soil: Not fussy, though growth is enhanced is soils are well drained and moderately amended with organic matter.
Watering: Regular
Pruning: Not needed.
Propagation: Sow seeds in the early fall in Phoenix and other mild climates. Seed germination can take up to 4 weeks. Thin out seedlings to 8" to 12" apart.
Disease and pests: None
Additional comments: Nice old fashioned plant for mixed, mesic flower gardens. Seldom found in Phoenix gardens. Delphinium flowers are reportedly moderately toxic if ingested, though the mode of action and lethal human dosage are unknown.