Delphinium grandiflorum (large-flowered delphinium) — perennial

Overview

Delphinium grandiflorum is a perennial in the genus Delphinium, part of the Ranunculaceae family. Delphinium grandiflorum grows best in full sun and partial shade, and tolerates well-drained and loamy soils and neutral and slightly acidic pH. Its UK hardiness is rated H5. Suggested uses include borders and cut flowers. It is native to E & N Asia.

About

Delphinium grandiflorum is a perennial in the Ranunculaceae valued for its large-flowered blooms, commonly seen in blue and white forms. It flowers in the UK from June to August. Plant in a sheltered, sunny or partly shaded spot with moist, well-drained loamy soil of neutral to slightly acidic reaction. Wear gloves and other protective equipment when handling, as the plant is harmful if eaten.

Wikipedia contributors, CC BY-SA 4.0 — Delphinium grandiflorum

About the genus

Delphinium is a genus of about 300 species of annual and perennial flowering plants in the family Ranunculaceae, native throughout the Northern Hemisphere and also on the high mountains of tropical Africa. The genus was erected by Carl Linnaeus.

Wikipedia contributors, "Delphinium", CC BY-SA 4.0 — Delphinium

In the garden

Delphinium grandiflorum originates from eastern and northern Asia and is grown for summer blossoms rather than as a long-lived clump. In the UK it flowers from June to August and is typically treated where necessary as a shorter-lived perennial. Its place of origin gives it a preference for a position that receives good light but some protection from the harshest exposure. Give the plant full sun or partial shade and a moist, well-drained loamy soil that is neutral to slightly acidic. Sit it in a sheltered spot to reduce wind exposure and soil drying; the species is H5, which translates as hardy across most of the UK. Keep soil evenly moist rather than waterlogged and avoid heavy, compacted ground. Use Delphinium grandiflorum in mixed borders where summer stems can be cut for vases; the plant is often grown for cut flowers. Handle with care: it is harmful if eaten, so wear gloves and other protective equipment when pruning or lifting, and consult the HTA guide to potentially harmful plants for further information and contact numbers regarding pets.

Growing conditions

Best soil and position for Delphinium

Sunlight: full sun, partial shade
Soil type: well-drained, loamy
Soil pH: neutral, slightly acidic
Soil moisture: moist
Exposure: sheltered
UK hardiness: H5

Plant details

Delphinium grandiflorum size, habit and characteristics

Plant type: perennial
Suggested uses: borders, cut flowers
Native to: E & N Asia
Toxicity: Humans/Pets: Harmful if eaten. Wear gloves and other protective equipment when handling. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants

Care notes

Pruning and caring for Delphinium grandiflorum

Cultivation: Prefers cool summers and well-drained soil. Avoid waterlogging. Stake tall varieties to prevent flopping.
Pruning: Deadhead spent flowers to encourage further blooming. Cut back after flowering to promote fresh growth.
Propagation: Seed,division

Frequently asked questions

How do I grow Delphinium grandiflorum?

Prefers cool summers and well-drained soil. Avoid waterlogging. Stake tall varieties to prevent flopping.

Where is the best place to plant Delphinium grandiflorum?

Delphinium grandiflorum prefers full sun and partial shade. It suits sheltered positions.

What soil does Delphinium grandiflorum need?

Delphinium grandiflorum grows best in well-drained and loamy soil. It prefers neutral and slightly acidic soil. Aim for soil that stays moist.

How do I prune Delphinium grandiflorum?

Deadhead spent flowers to encourage further blooming. Cut back after flowering to promote fresh growth.

Is Delphinium grandiflorum hardy in the UK?

Delphinium grandiflorum has an RHS hardiness rating of H5, meaning it is hardy in most of the UK, tolerating -15 to -10°C.

How do I propagate Delphinium grandiflorum?

Seed,division.

Is Delphinium grandiflorum toxic?

Humans/Pets: Harmful if eaten. Wear gloves and other protective equipment when handling. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants.

More in the Delphinium genus

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