How to Grow Delphinium Pacific Giants

Delphinium Pacific Giants

Delphinium × elatum 'Pacific Giants'

flower

Delphinium Pacific Giants are stunning tall perennial flowers known for their impressive spikes of blue, purple, pink, or white blooms that can reach 4-6 feet in height. These showstopping flowers are popular in cut flower arrangements and cottage gardens, providing vertical interest and dramatic color. They require staking and careful attention to drainage but reward gardeners with magnificent summer flowering displays.

Looking for a specific variety?

Blue Bird Black Knight Galahad King Arthur Summer Skies Astolat

Growing Conditions

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Sun: Full sun, 6-8 hours daily; partial shade in hot climates helps prevent wilting

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Water: Keep soil consistently moist but not waterlogged; water deeply at the base to prevent fungal issues; increase watering during hot, dry periods

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Spacing: 24 inches

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Days to maturity: 90-120 days from transplant to first flowers

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Planting depth: Surface sow seeds (light-dependent) or plant transplants at soil level

Soil

Type: Well-draining fertile loamy soil

pH: 6.0-7.0

Amendments:

Compost Peat moss Aged manure Perlite or grit for drainage

Growing Zones

Find your zone →

Thrives in zones 3-7, prefers cooler climates

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b

Growth Stages

Seedling

3-4 weeks

Tiny seedlings with first true leaves emerge; very delicate and prone to damping off

Start indoors in cool conditions (60-65°F); maintain high humidity without waterlogging; provide good air circulation; avoid transplanting until 2-3 true leaves appear

Vegetative Growth

6-8 weeks

Young plants develop sturdy stems and multiple sets of deeply lobed green leaves; form a robust basal rosette

Gradually harden off before planting out; space 24 inches apart; water regularly; apply balanced fertilizer every 2 weeks; pinch tips to encourage branching if desired

Flower Stalk Development

3-4 weeks

Tall central stems emerge, reaching 4-6 feet; buds form along the flower spike in tight clusters

Install sturdy stakes early; tie stems loosely as they grow; avoid excessive nitrogen which causes weak growth; water consistently; begin applying low-nitrogen fertilizer

Flowering

4-6 weeks

Spectacular flower spikes open progressively from bottom to top with densely packed florets in shades of blue, purple, pink, or white; peak bloom lasting 4-6 weeks

Deadhead spent flowers to extend blooming; water at base only; stake securely to prevent wind damage; monitor for powdery mildew; apply fungicide if needed

Post-Flowering & Dormancy

Ongoing through fall and winter

After flowering, seed pods develop; foliage begins to decline; plant enters dormancy as temperatures cool

Allow some flowers to go to seed for self-sowing if desired; cut back stems to 12 inches after frost; divide established plants every 3-4 years in fall; mulch for winter protection in colder zones

Companion Planting

Plan your garden →

Plant with:

Lavender Catmint Salvia Coreopsis Achillea Peonies Foxgloves Roses Alliums Yarrow

Avoid planting near:

Fennel Kochia Brassicas in dense plantings that shade the delphinium

Common Pests

Improve air circulation; avoid overhead watering; remove affected foliage; apply copper fungicide in cool, moist conditions
Ensure good air circulation; avoid wetting leaves; spray with sulfur or neem oil at first signs; choose resistant varieties
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Hand-pick in early morning; use copper tape around stems; beer traps; encourage natural predators like ground beetles
Increase humidity; spray with water; use insecticidal soap or neem oil if severe
Ensure excellent drainage; avoid planting in low-lying areas; remove and destroy infected plants; apply sulfur to soil
Remove affected leaves; spray with spinosad; encourage parasitic wasps

Uses

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Edible Flowers

Culinary

Delphinium petals are edible and can be used to garnish salads, desserts, and beverages for ornamental purposes, though they have minimal flavor and are primarily decorative. [source]

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Cut Flower Arrangements

Household

Delphiniums are premium cut flowers prized by florists for their dramatic tall spikes and rich colors; they are a staple in wedding bouquets, arrangements, and floral designs. [source]

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Dried Flower Crafts

Craft

Delphinium flowers can be dried and preserved for use in dried arrangements, wreaths, pressed flower crafts, and decorative displays that maintain their color for months. [source]

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Traditional Herbal Use

Medicinal

Historically, delphinium has been used in traditional medicine for various purposes, though modern use is limited and safety should be verified; seeds contain alkaloids and should not be ingested. [source]

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Pollinator Support

Wildlife

Tall delphinium spikes attract bees, butterflies, and hummingbirds, providing excellent nectar and pollen sources throughout the summer flowering season. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Cut flowers in early morning when the bottom 1/3 of the spike has opened; use sharp florist scissors and cut stems at an angle; place immediately in cool water with floral preservative; remove lower leaves. Cut flowers last 7-10 days in a vase. For garden display, allow some flowers to remain for seed production.

Fun Facts

🌱 Delphinium Pacific Giants can reach 4-6 feet tall, making them among the tallest perennial flowers in a cottage garden; some cultivars have been bred to exceed 8 feet in height.
🌱 The name 'delphinium' comes from the ancient Greek word 'delphis' meaning 'dolphin,' as the flower's nectar spur resembles a dolphin's tail.
🌱 These flowers have been hybridized extensively since the early 1900s, with the 'Pacific Giants' series developed in California by renowned breeder Frank Reinelt in the 1950s, revolutionizing delphinium breeding.

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