Delphinium Guardian Blue

Description

Delphinium ‘Guardian Blue’ – delphinium

Botanical name: Delphinium ‘Guardian Blue’
Common names: Delphinium
Family: Ranunculaceae
Plant type: Herbaceous perennial
Habit: Tall, upright, clump-forming
Pot size: 2–3 litre pot
Eventual size: Approx. 1.2–1.5m tall × 45cm spread
Foliage: Deeply divided, lobed green leaves; deciduous
Flowers: Tall, dense spires of rich blue flowers in early to midsummer (June–July)
Scent: Not notably scented
Aspect / light: Full sun
Soil: Fertile, moist but well-drained; dislikes wet or dry extremes; any pH
Hardiness: RHS H6 (hardy, to about −20°C); USDA zones 3–7
Exposure: Sheltered from strong winds; staking essential
Native range: Garden form; the genus is native to the northern hemisphere
Toxicity / pet & child safety: Toxic — all parts of delphinium are poisonous if eaten, and the sap can irritate skin; keep away from children and pets, and wear gloves when handling

Delphinium ‘Guardian Blue’ is a magnificent border perennial with tall, dense spires of rich blue flowers in early summer. Stately and dramatic, it is a classic for the back of cottage and mixed borders.

GardenAdvice notes

The magnificent aristocrat of the cottage-garden border, delphinium is grown for its tall, stately spires densely packed with flowers in early to midsummer, giving unrivalled vertical drama and some of the purest colours in the garden. It needs good soil, sun, shelter and — essentially — staking, but rewards the effort with a breathtaking display, and often a second, smaller flush if cut back after flowering.

Growing & planting

Plant in spring or autumn in fertile, moist but well-drained soil in full sun, in a spot sheltered from strong winds, which can snap the tall stems. Improve the soil with compost. Crucially, stake the stems early, as they grow, since they are top-heavy and easily broken. Space about 45–60cm apart. Protect emerging shoots from slugs.

Care & maintenance

Stake early and thoroughly — this is essential. Water and feed well in the growing season. After the first flowers fade, cut the flowered spikes back to encourage a second, later flush. Cut down all old growth in autumn. Slug protection in spring is vital, as slugs and snails adore the young shoots. Divide congested clumps in spring.

Propagation

• Division: Lift and divide established clumps in spring, as growth begins.
• Cuttings: Take basal cuttings in spring.
• Seed: Seed strains such as this can be raised from seed sown in spring.

Pests & diseases

Slugs and snails are the great enemy, devastating the young spring shoots if unprotected. Powdery mildew can occur later in the season. The tall stems are easily broken by wind if not staked. Given protection and support, it is magnificent.

Uses in the garden

Superb at the back of cottage, mixed and herbaceous borders, where its tall, stately flower spires give unrivalled vertical drama and classic early-summer colour; excellent for cutting.

Wildlife value

The flowers are attractive to bees, particularly long-tongued bumblebees, which are drawn to the spires in early summer.

Toxicity & safety

Delphinium is toxic — all parts are poisonous if eaten, and the sap can irritate skin. Keep it away from children and pets, site it accordingly, and wear gloves when handling or cutting it.

GardenAdvice tip

‘Guardian Blue’ gives you the classic delphinium spectacle — tall, densely packed spires of rich, pure blue, one of the great sights of the early-summer border. Two things are essential: stake it early, as the stems are top-heavy and snap in wind, and protect the young spring shoots from slugs, which adore them. Cut back after flowering for a second, smaller flush. Do note all parts are poisonous.

Our plants are guaranteed for 24 months for more details Click Here