Ornamental Allium
Allium
Round drumstick heads floating on bare stems, with tired foliage below that is worth hiding behind a neighbor.
- Type
- Flower · Perennial
- Botanical family
- Allium (onion family)
- Foliage color
- Green
- Flower color
- Purple and violet
- Sunlight
- Nothing less than full sun.
- Watering
- Water while it is growing, then keep it dry once dormant.
- Feeding
- A low-phosphorus bulb feed once in spring.
- Frost tolerant
- Yes
- Flowering
- May
- Pruning
- Leave the stems until the foliage has died back completely, then take them off.
- Overwintering
- Hardy in most gardens; mulch where winters run very cold or very wet.
- Mar–May Spring Growth
- May–Jul Flowering
- Jul–Sep Growing
- Sep–Dec Leaf Fall
- Jan–Mar Leaf Fall
- Plant spacing
- 5.9 in
- In-row spacing
- 5.9 in
- Between rows
- 7.9 in
- Square-foot density
- Not suited to SFG
- Root system
- A bulb with fine roots beneath it
- Working depth
- 4–10 in
- Can reach
- 16 in down where the soil allows
- Spread
- 4–8 in across, about 0.5–1× the width of the plant
- Shallowest pot
- 8 in of soil
Roots thread down from the base plate each season and are shed each season, and they go no further out than the leaves. Everything the bulb will store for next year is gathered in that narrow circle before the foliage yellows, which is why cutting the leaves early costs a flower.
The habit is Ornamental Allium’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Cats and dogs
- Recorded toxic
Recorded as toxic to cats and dogs by Pet Poison Helpline.
The Pet Poison Helpline Onions row prints its scientific name as the bare genus Allium, which is the rank our catalog names, and its text treats the Alliums as a group. It names dogs and cats. The ASPCA has no genus-level Allium row: its rows are Onion, Garlic, Chives and Leek, each a species we do not name here. Cornell carries the genus but names cattle, horses and children.
Green-leaved flowers, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com