Allium (Ornamental) Growing Guide

Allium

Crop Rotation Group

Allium (Onion family) ●

Soil

Average garden soil with excellent drainage.

Position

Full sun.

Frost tolerant

Excellent. Most of the popular ornamental onions are hardy to -25F (-32C).

Feeding

Topdress with rich compost in spring, when new growth appears. Fertilize with a liquid fertilizer in early summer, when the plants are in full leaf.

Spacing

Single Plants: 11" (30cm) each way (minimum)
Rows: 11" (30cm) with 11" (30cm) row gap (minimum)

Sow and Plant

Set out dormant bulbs in the fall, or transplant container-grown plants in early spring. Cover the bulbs to four times their depth with loose soil. Allow 12in (30cm) between bulbs of most varieties; very small species can be planted closer.
Our Garden Planner can produce a personalised calendar of when to sow, plant and harvest for your area.

Notes

Ornamental alliums often have a light lilac fragrance. Very tall cultivars may need staking to keep them upright. Lavender, purple, pink and white are the most common flower colors.

Harvesting

When using ornamental alliums as cut flowers, make a clean cut with a sharp knife or razor blade when less than half of the florets are open. As the flowers fade in the garden, trim them off with scissors or pruning shears.

Planting and Harvesting Calendar

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Pests which Affect Allium (Ornamental)

Aphids (General)

Slug

Snail

Plant Diseases which Affect Allium (Ornamental)

Allium White Rot