Delphinium elatum: Majestic Spires for the Summer Garden

Quick Facts

• Zones: 1–10, 14–24, 32, 34, 36–41
• Sun: Full sun
• Water: Regular

Description

Delphinium's towering bloom spikes (5–6 feet) are a summer garden staple. Flowers range through blues, purples, cool pinks, cream, and white—flat, 2-inch blooms on narrow upright spikes. Dark green, deeply lobed foliage forms 1–2 foot clumps.

Growing Requirements

• Climate: Cool, moist summers; chilly but not severe winters.
• Soil: Rich, porous, neutral pH (amend acid soil). High organic matter and phosphorus.
• Spring Care: When shoots appear, thin to 2–3 strongest; apply complete fertilizer.
• Staking: Stake early.
• After Bloom: Cut back stalks, leave basal foliage; fertilize new growth for fall rebloom.

Longevity and Alternatives

Even in ideal conditions, delphiniums are short-lived. Annual spring division may extend life. Outside preferred zones, treat as annuals. Plant fall in mild-winter areas; after frost danger in hot-summer regions.

Related Types:

• Pacific Hybrids – spikes to 7 feet.
• D. belladonna hybrids ('Bellamosum') – hardier, more disease-resistant, shorter but more numerous spikes.
• Chinese delphinium (D. grandiflorum) – more forgiving, 1.5–2 feet, blue shades.