Ornamental Onion

Ornamental Onion (Allium 'Luna') holds its yellow flower heads on straight bare stems about 600mm tall, above a narrow tuft of foliage barely 200mm across. That combination of height without width is what makes ornamental alliums so useful: they slot between existing plants and lift colour above them without taking up bed space. Bees work the flower heads steadily while they last.

Why you'll love it

• Height with almost no footprint. At 600mm tall and only 200mm wide it threads through an existing border rather than displacing anything.
• Yellow is the rare one. Most ornamental alliums are purple, so a yellow flowered form sits differently against grey and green foliage.
• Bees and butterflies come to it. The open flower heads are easy landing platforms and stay in flower over a useful stretch.
• Frost hardy and drought tolerant. It handles cold winters and dry summers, and it wants no attention while dormant.

Where it works best

Borders and edging. Plant 20cm apart for a bold massed display. Alliums always read better in groups of ten or more than as scattered single stems.

Mass planting and feature groups. Drift them through low perennials or grasses so the bare stems rise out of soft foliage, which also hides the leaves as they die back.

Pots and containers. A deep pot with sharp drainage suits them well, and a container can be moved to the front while flowering and out of the way afterwards.

Growing ornamental onion in Australia

Position and climate. Full sun, all day if possible. It suits cool temperate, warm temperate and Mediterranean gardens, and it is frost hardy. Humid tropical and subtropical summers rot the bulbs, so it is not a plant for the far north.

Soil. Free draining above everything else. Sandy or gravelly ground is ideal, heavy clay needs a raised bed, and bulbs sitting in wet soil while dormant will not return.

Water and feed. Water through active growth and flowering, then stop once the foliage yellows. A light application of a balanced fertiliser as growth begins in late winter is enough for the season.

After flowering. Let the foliage die down naturally rather than cutting it green, because the bulb feeds itself during that period. Leave the bulbs in place in a well drained bed, or lift and store them dry over summer in wetter gardens.

What to expect when it arrives

It is supplied in 140mm pots sold in packs of ten, which is the right quantity for the massed display this plant is grown for. Ten plants at 20cm spacing fill roughly a square metre of border with real presence.

Depending on the season your plants may arrive in leaf, in bud, or cut back and dormant. Dormant stock is not dead: it is simply resting and will shoot when the temperature suits. Plant at the same depth as the pot and water in. Delivered Australia wide, with delivery from $29.95 and a minimum order of $300 before delivery, and every plant carries our 30 day healthy plant guarantee.

Plant care guides and related reading

• Low growing plant ideas for borders
• Browse plants that attract bees and butterflies
• Perennials for a cottage garden

Common questions

Is it safe around cats and dogs?

No. Every plant in the onion family, ornamental ones included, is toxic to cats and dogs if eaten, and the bulbs are the most concentrated part. Plant it where a digging pet cannot reach the bulbs.

Will it come back each year?

Yes, in a well drained sunny bed it dies down after flowering and returns the following season. The one thing that ends it is wet soil over its dormant period.

Does the foliage look untidy?

The leaves yellow and collapse as the flowers finish, which is normal for a bulb. Planting through low perennials or grasses hides that stage completely.

How many should I plant together?

At least ten, spaced 20cm apart. A single pack covers about a square metre, and alliums lose their effect entirely when planted as scattered individuals.