Delphinium grandiflorum Summer Blues® | Siberian Larkspur

Delphinium grandiflorum Summer Blues® | Siberian Larkspur – Premium Cut Flower Seeds

Delphinium grandiflorum Summer Blues® is a compact, early-flowering larkspur variety prized for its intensely vibrant sky-blue blooms and excellent garden performance. Unlike tall traditional delphiniums, Summer Blues® forms neat, bushy plants that flower reliably throughout the summer, making it a favourite for both cut-flower growers and ornamental gardeners.

Its silky, richly coloured blossoms bring a refreshing cool tone to bouquets, borders, and cottage-style plantings. Ideal for smaller gardens, container growing, and for growers seeking a dependable, easy-care delphinium with professional-quality results.

Plant Information

• Latin name: Delphinium grandiflorum
• Variety: Summer Blues®
• Type: Hardy perennial (often grown as an annual)
• Height: 30–40 cm
• Spread: 25–30 cm
• Flowering period: June–August
• Position: Full sun
• Soil: Well-drained, fertile soil

How to Grow

• Sow indoors: February–April
• Germination: 14–21 days at 15–20°C
• Sowing depth: Lightly cover with fine compost or vermiculite
• Transplant: When seedlings are large enough to handle
• Plant out: After the last frost into full sun
• Care: Deadhead spent blooms to encourage continuous flowering

Ideal For

• Cottage gardens
• Blue colour-themed plantings
• Summer bouquets
• Pollinator-friendly gardens
• Compact spaces and containers

Bring the cool elegance of true summer blue into your garden with this reliable, richly coloured Siberian larkspur — a must-have for every blue-flower lover and a standout performer for cut-flower growers.

Why Grow Summer Blues®?

• 🌿 Compact habit – perfect for beds, borders, and containers
• 💙 Intense sky-blue flowers that hold colour beautifully
• ✂️ Great for cutting – elegant stems with long-lasting blooms
• 🌱 Fast-growing and blooms in the first season
• ❄️ Cold-tolerant (Siberian type) with strong outdoor performance