Growing Allium (Flowering Onion): Dramatic Globes for Garden and Bouquets

Growing Allium (Flowering Onion)

Pronunciation: al'ee-um

Bulb size: 22–24 cm / 12–14 cm / 6–8 cm (varies by variety).

The genus Allium (Latin for "garlic") includes many garden plants growing from bulbs or rhizomes. Dense balls of color atop strong stems make excellent garden displays and bouquets. Colors range from purple, burgundy, lilac, silvery amethyst, pink, blue, to yellow and white. Some have scented blooms (pleasant, not oniony); bulbs and leaves may smell of onions.

Light and Watering

Most need full sun (6–8 hours direct) and well-drained soil. Longest-lived where soil is dry during summer dormancy.

Planting

Plant more shallowly than similar-sized bulbs: just 1–2 times bulb diameter deep.

Fertilizer, Soil, and pH

Prefer well-drained, fertile soil. Fertilize in fall and spring with bulb fertilizer.

Continuing Care

Leaf tips brown before bloom. Remove spent flowers (except sterile varieties like 'Globemaster') to prevent self-sowing.

Pests and Diseases

Few problems unless planted too shallowly or in wet soil.

Companions

Place behind heavy-foliage plants like Peonies and Iris. Good for bedding and mixed borders. Flower heads dry well.

Dividing and Transplanting

Rarely needed; can be done when bulbs are dormant.