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How to Grow Delphinium Dwarf Blue

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Delphinium Dwarf Blue

Delphinium grandiflorum 'Dwarf Blue'

flower

Delphinium Dwarf Blue is a compact ornamental flowering plant known for its vibrant blue spiky flower spires. This dwarf variety reaches only 12-18 inches tall, making it ideal for borders, containers, and small garden spaces. It blooms prolifically throughout the growing season with semi-double flowers arranged densely on upright stems.

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Example Delphinium Dwarf Blue timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Delphinium Dwarf Blue

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. First Delphinium Dwarf Blue blooms

    Around Jun 16

    ≈ 60 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Delphinium Dwarf Blue dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6-8 hours of direct sunlight daily for best flowering
💧
Water: Keep soil consistently moist but not waterlogged. Water deeply 1-2 times per week depending on heat and rainfall. More frequent watering needed during hot, dry periods. Reduce watering in cooler months.
📏
Spacing: 12-15 inches
📅
Days to maturity: 60-70 days to first flowers from seed, earlier from transplants
🌱
Planting depth: Seeds should be surface-sown or lightly pressed into soil (they need light to germinate); transplants planted at soil level

Soil

Type: Well-draining loamy soil with good organic matter
pH: 6.0-7.0
Amendments:
Compost Peat moss Perlite for drainage Lime if soil is acidic

Growing Zones

Find your zone →

Thrives in zones 2-8, performs best in cooler climates with consistent moisture

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

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Growth Stages

1

Seedling

2-3 weeks

Tiny seedlings emerge with simple cotyledons. True leaves develop within 2-3 weeks with characteristic serrated, palmate foliage.

Keep soil moist but not soggy. Provide bright light (grow lights if indoors). Maintain cool temperatures (60-70°F). Avoid fungal issues with good air circulation.

2

Vegetative Growth

3-4 weeks

Plant develops bushy foliage with increasingly compound leaves. Stems thicken and the plant grows to about half its mature height. No flower buds visible yet.

Water consistently. Begin fertilizing with balanced or slightly nitrogen-rich fertilizer every 2-3 weeks. Thin seedlings to proper spacing if needed. Harden off transplants gradually before planting outdoors.

3

Budding & Early Flowering

2-3 weeks

Flower spikes begin forming at stem tips. Buds are tightly packed along the inflorescence. First flowers open from the bottom up.

Continue consistent watering. Switch to balanced or slightly phosphorus-rich fertilizer to encourage blooming. Provide stake support if needed. Deadhead spent flowers below the stem to encourage branching.

4

Peak Flowering

3-6 weeks (extended with regular deadheading)

Dense spires of blue semi-double flowers in full bloom. Plant reaches mature height of 12-18 inches and is heavily covered in flowers.

Deadhead regularly to extend blooming period. Maintain steady watering without letting soil dry out. Fertilize every 3 weeks. Remove any yellowing or diseased foliage.

5

Seed Development & Second Bloom

Ongoing until frost

If not deadheaded, seed pods form and plant energy shifts to seed production. If deadheaded, plant may produce secondary flower spikes within 4-6 weeks.

Allow some flowers to go to seed if you want self-sowing next season, or continue deadheading for continuous blooms. Reduce fertilizer if allowing seeds to mature.

Companion Planting

Plan your garden →

Plant with:

Coreopsis Salvia Catmint Yarrow Russian Sage Lavender Dianthus Allium Echinacea

Avoid planting near:

Fennel Tree roots competing for nutrients Overly wet areas with poor drainage

Common Pests

  • and

    Handpick in early morning or evening. Use copper tape barriers around plants. Apply organic slug bait containing iron phosphate. Remove debris where they hide.

  • Spray foliage with water to dislodge. Use insecticidal soap or neem oil. Maintain adequate humidity. Increase air circulation.

  • Spray with strong water stream to remove. Use insecticidal soap or neem oil. Encourage natural predators like ladybugs. Apply horticultural oil in early morning.

  • Improve air circulation by spacing plants adequately. Water at soil level, avoiding wet foliage. Apply sulfur dust or fungicidal spray. Remove affected leaves.

  • and (various fungi)

    Remove infected foliage promptly. Avoid overhead watering. Apply copper fungicide or sulfur. Ensure good air circulation around plants.

Uses

🍳

Not for consumption

Culinary

Delphiniums are toxic and should never be ingested by humans or pets. All plant parts contain poisonous alkaloids. [source]

🏠

Cut flowers and arrangements

Household

Delphinium Dwarf Blue is excellent for fresh flower arrangements, adding height and vibrant color to bouquets. The flowers last 7-10 days in a vase with proper water conditioning. [source]

🎨

Dried flowers

Craft

Flowers dry beautifully and can be used in dried arrangements, pressed flower crafts, and decorative projects. Hang bundles upside down in a dark, dry location for 2-3 weeks. [source]

🦋

Pollinator attraction

Wildlife

The tall spikes attract bees, butterflies, and hummingbirds to the garden, supporting pollinator populations and native beneficial insects. [source]

🏠

Garden ornament and border plant

Household

The dwarf compact habit makes this variety perfect for creating colorful borders, container plantings, and adding vertical interest to small garden spaces without requiring tall stakes. [source]

Harvest Tips

Cut flower spikes for arrangements when 3/4 of the flowers on the spike are open. Cut early in the morning with sharp, clean scissors. Cut stems at a 45-degree angle and immediately place in cool water. Remove lower foliage below the waterline. Cut back spent flower spikes at the base to encourage secondary flowering. Allow some flowers to mature and dry on the plant if you want seeds for next season.

Fun Facts

  • 🌱 The genus name Delphinium comes from the Greek word 'delphis' meaning 'dolphin' because the flower's nectar spur resembles a dolphin's nose.
  • 🌱 Delphiniums have been cultivated in gardens for over 2,000 years and were particularly prized in medieval monastery gardens for their brilliant blue color.
  • 🌱 The intense blue pigments in delphinium flowers are due to delphinidin anthocyanins, the same compounds that give blueberries their color, though delphiniums are toxic while blueberries are not.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Deadhead Full Sun pH Transplant True Leaves
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