Allium caeruleum

One of the few truly blue flowering bulbs, Allium caeruleum produces elegant globe-shaped flower heads made up of masses of tiny star-like blooms in a striking sky-blue shade.

Held on slender upright stems above narrow green foliage, these delicate flower heads bring a light and airy feel to borders and naturalistic planting schemes. Their unusual colouring makes them particularly effective when planted amongst ornamental grasses, pastel perennials or warm-toned flowers where the blue tones can really stand out.

Native to the mountainous regions of Central Asia, Allium caeruleum has long been admired for both its unique colouring and easy-going nature. It is a reliable and easy-to-grow ornamental allium that will gradually naturalise over time, forming attractive drifts in sunny, well-drained borders.

Perfect for cottage gardens, prairie planting, gravel gardens and pollinator-friendly borders, the flowers are highly attractive to bees and beneficial insects throughout late spring and early summer.

Plant in groups for the most natural and eye-catching display.

Planting Instructions

When to Plant:

Plant Allium bulbs in autumn (September–November) before the ground freezes. This allows roots to establish for strong flowering the following season.

Where to Plant:
Choose a sunny position with well-drained soil. Alliums are ideal for borders, gravel gardens and naturalistic planting schemes. Avoid areas where soil remains wet over winter.

How to Plant:

• Depth: Plant bulbs about 8–10 cm (3–4 inches) deep.
• Spacing: Space bulbs about 8–10 cm (3–4 inches) apart.
• Soil Prep: Improve soil with compost. In heavier soils, add grit or sharp sand to improve drainage.

Watering:
Water after planting. Once established, Alliums require very little additional watering unless conditions are particularly dry.

Aftercare Tips:

• Allow foliage to die back naturally after flowering to feed the bulb.
• Deadhead if desired, or leave seed heads for added interest.
• Avoid excessive moisture in winter to prevent bulb rot.

Top Tip:
Plant in drifts through borders or gravel gardens for a natural look – the clear blue flowers combine beautifully with ornamental grasses and soft pastel planting.

Plant Details

Flowering Period:
June - July (depending on season and conditions)

Height:
20–28" (50–70cm) (approx.)

Position:
Full sun

Hardy Perennial