Allium caeruleum – Blue ornamental onion for a beautiful garden

Allium caeruleum, also known as blue ornamental onion, is a beautiful bulbous perennial that adds a striking accent to your garden with its intense blue umbels. This ornamental allium is perfect for borders, rock gardens, cutting gardens, and pots, and its nectar-rich flowers attract bees, butterflies, and other pollinators.

Impressive blue flowers

Allium caeruleum produces large, rounded flower clusters 5–10 cm across, composed of numerous star-shaped, light blue flowers. The flowers rise on sturdy stems 60–90 cm tall, allowing them to tower over most border plants and add a beautiful vertical structure to your garden. The long flowering period from late spring to early summer (May–June) makes the plant a real eye-catcher.

Growth and care

Allium caeruleum is easy to care for and drought-tolerant, making it suitable for various garden varieties. The plant thrives in a sunny spot in well-drained soil, preferably humus-rich and neutral to slightly alkaline.

Some care tips:

• Plant the bulbs in autumn or early spring, at a depth of 8–10 cm.

• Combine with shorter perennials such as lavender, salvia or geranium for a layered effect.

• After flowering, remove the flower stems if desired, but allow the foliage to die back to provide the bulb with nutrients for the following season.

Cultivation information

• Location: Full sun

• Soil: Well-drained, humus-rich

• Height: 60–90 cm

• Flowering period: May – June

• Uses: Borders, rock gardens, cutting gardens, pots

• Maintenance: Low, drought tolerant, propagate bulbs after a few years

Attractive to pollinators

The intense blue flowers of Allium caeruleum are a rich source of nectar for bees, bumblebees, and butterflies, making the plant not only aesthetically pleasing but also contributing to healthy biodiversity in your garden.

Combination options

Allium caeruleum combines beautifully with both colorful summer bloomers and evergreen perennials. Consider combinations with:

• Lavender (Lavandula) for a purple-blue color palette

• Rudbeckia or Echinacea for a striking contrast

• Low ground covers such as Thymus or Nepeta to make the stems stand out even more

Key Features

• Strong, upright with intense blue flower clusters

• Sturdy stems of 60–90 cm

• Flowering period: May – June

• Easy to maintain and drought tolerant

• Bee and butterfly friendly

• Perfect for borders, rock gardens, cutting gardens and pots

• Bulbs can last for several years with proper care

In short: Allium caeruleum is a lush and easy-care ornamental onion that adds beautiful vertical structure and blue color to your garden. Perfect for gardeners who want to create a striking, ecologically valuable border with a long bloom period and pollinator appeal.