How to Grow Delphinium

Delphinium

Delphinium elatum

flower

Delphiniums are tall, stately perennial flowers prized for their striking spikes of blue, purple, pink, or white blooms that can reach 3-6 feet in height. These classic cottage garden flowers bloom in mid-summer and attract pollinators while adding dramatic vertical interest to garden landscapes. They are relatively short-lived perennials that often reseed themselves.

Looking for a specific variety?

Black Eyed Angels Blue Bird Camelliard Magic Fountains Pacific Giants New Millennium

Growing Conditions

☀️

Sun: Full sun, 6-8 hours daily; afternoon shade helpful in hot climates

💧

Water: Keep soil consistently moist but not waterlogged. Water at base to avoid powdery mildew. Provide 1-1.5 inches weekly; increase during hot, dry periods.

📏

Spacing: 24 inches

📅

Days to maturity: 60-100 days from transplant to first bloom; 120-150 days from seed

🌱

Planting depth: Seeds need light to germinate; surface sow or barely cover. Transplants at same depth as nursery pots.

Soil

Type: Well-draining, fertile loamy soil rich in organic matter

pH: 6.0-7.0

Amendments:

Compost Aged manure Bone meal Perlite or coarse sand for drainage

Growing Zones

Find your zone →

Zones 2-8; prefer cooler climates and struggle in hot, humid southern regions

2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a

Growth Stages

Seedling

3-4 weeks

Tiny leaves emerge; slow initial growth. Takes 2-3 weeks to develop true leaves.

Keep soil moist and provide bright light. Thin seedlings to prevent crowding. Seeds benefit from cold stratification (30 days in refrigerator).

Vegetative Growth

6-8 weeks

Develops basal rosette of deeply lobed foliage and establishes strong root system. Plant reaches 12-18 inches.

Install sturdy stakes early to support future height. Water consistently. Fertilize monthly with balanced fertilizer.

Bud Formation

3-4 weeks

Flower spikes emerge from center of plant, reaching toward sky. Tiny buds visible along the developing raceme.

Increase watering as flower spike lengthens. Apply flower fertilizer low in nitrogen. Stake tall varieties securely.

Flowering

4-6 weeks

Spectacular dense spikes of flowers open from bottom upward, typically in shades of blue, purple, pink, or white. Each spike can be 1-2 feet long.

Deadhead lower spent flowers to encourage upper blooms. Water at base only. Support with stakes if windy. Cut for arrangements.

Seed Set & Decline

3-4 weeks

If allowed to remain, flowers fade and seed pods develop. Plant begins senescence.

Cut back spent flower spikes to 12 inches if you want repeat blooms in 4-6 weeks. Alternatively, allow seeds to mature and self-sow for next year.

Companion Planting

Plan your garden →

Plant with:

Roses Peonies Lavender Catmint Yarrow Salvia Foxgloves Baby's breath Alliums

Avoid planting near:

Fennel Kochia Plants requiring dry conditions

Common Pests

Remove and destroy infected plant parts. Inject Bacillus thuringiensis (Bt) into hollow stems in spring. Grow susceptible plants in containers to isolate them.
Ensure good air circulation. Water at base, not foliage. Apply sulfur dust or neem oil at first sign. Avoid overhead watering.
and
Hand-pick at night. Use copper barriers or slug traps. Apply diatomaceous earth around plants.
Remove affected leaves. Improve air circulation. Avoid wetting foliage. Apply copper fungicide if severe.
Spray with water to dislodge. Apply insecticidal soap or neem oil. Increase humidity.

Uses

🍳

Floral Garnish & Decoration

Culinary

Delphinium flowers are sometimes used as edible garnishes for special occasion desserts and dishes, adding dramatic color and an elegant presentation. Ensure they are grown without pesticides if intended for consumption. [source]

🏠

Cut Flower Arrangements

Household

Delphiniums are among the most prized cut flowers for floral design, providing height, color, and structure to bouquets and arrangements. They pair beautifully with roses, peonies, and other garden flowers. [source]

💊

Traditional Herbal Medicine

Medicinal

Historically, delphinium was used in traditional medicine for various purposes, though modern herbalism rarely uses it due to toxicity concerns. All parts of the plant contain toxic alkaloids and should not be ingested. [source]

🎨

Pressed Flowers & Drying

Craft

Delphiniums dry beautifully and retain their color well, making them ideal for pressed flower crafts, potpourri, and dried arrangements. Hang-dry by bundles in a warm, dark location. [source]

🦋

Pollinator Garden

Wildlife

Delphiniums are excellent nectar sources that attract bees, butterflies, and hummingbirds throughout their blooming season. Planting them supports vital pollinator populations in the garden ecosystem. [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 stems are turgid and lower flowers are open but upper buds are still tight. Strip lower leaves and immediately place in water. Change water every 2-3 days. Use floral preservative to extend vase life to 7-10 days. Harvest seed pods after they turn brown but before they split; hang in paper bags to dry and collect seeds.

Fun Facts

🌱 The name 'delphinium' comes from the Greek word 'delphis' meaning dolphin, referring to the flower's fanciful resemblance to a leaping dolphin.
🌱 Delphiniums contain toxic alkaloid compounds throughout the entire plant and should never be ingested; even handling can cause skin irritation in sensitive individuals.
🌱 The legendary 'Black Delphinium' was a breeding goal for decades but cannot technically be achieved, as the darkest available cultivars are deep purple or midnight blue due to natural pigment limitations.

Want personalized planting timelines?

Get started free