Allium is a superb flower, famous for its surprising ornamental floral scapes.
Key Allium flower facts
Height – 8 to 40 inches (20 to 100 cm)
Exposure – full sun
Soil – ordinary, better if acidic
Flowering – May to July
Easy to grow, it is perfect in flower beds or in pots and garden boxes to decorate your terrace or balcony.
Allium giganteum is planted in fall more or less 4 to 5 inches (10 to 12 cm) deep in light soil.
- Allium loves high sun exposure.
- Soil must be light and drain well, and even poor soil is fine.
- When acidity hovers between 5.5 and 6.5, blooming is maximized, but it’ll still grow fine if not the case.
A good tip to know how deep to plant it is to multiply the height of the bulb by 3. If it is 2 inches (5 cm) tall, plant 6 inches (15 cm) deep.
- Proceed to group 10 or 15 bulbs close together to create clustered spots of color.
- Plant bulbs more or less 8 inches (20 cm) apart.
- Look up our advice on planting bulbs.
- Learn how to plant bulbs in flooded or clay soil.
Pruning and caring for allium
Caring for allium is extremely easy, since the needs of this perennial bulb plant are not difficult to meet.
In both pots and in the ground, they will bear nice flowers without asking you to care for them.
- Cut wilted flower scapes as they die off, cutting the stem off as short as you can.
- Only cut leaves back when they have already turned yellow because that is when the bulb is stocking up on nutrients for the next blooming cycle.
- No need to add fertilizer.
Note that allium leaves tend to turn yellow before or after the blooming of the large umbels, and so it helps to plant ground-covering perennials around the giant onion plants, to cover the wilted leaves and only let the flower stem stick out.
As for pot-growing allium, remember to water regularly because water needs are higher due to the fact that potted plants tend to dry off faster.
All there is to know about allium
The different Allium varieties all boast superb flowers bunched up in balls and the size and color of this ball depends on the variety.
In flower beds or along edges, and also along a wall or simply plunked in the middle of the yard, the ornamental impact of this plant is guaranteed!
- Allium giganteum, thanks to its tall bearing, is perfect to line the back of a flower bed.
It is also used in flower bouquets, because the foliage and the flowers both can be used to make appealing bouquets.
Smart tip about allium
For the taller species you can stake the stem to keep it from folding under the wind. Nice for this is to use bamboo, it is perfectly suited and actually enhances the visual impact of the plant.