Ornamental allium are just a small part of a large genus of over 400 species of mostly onion scented herbs that includes the common onion, leek, garlic, chive and shallot. This makes gardeners wonder if they should include them in their ornamental gardening plans since it conjures up images of supermarket produce. Allium blooms create high drama and interest in the garden and range in color from white, yellow, pink to purple, few to a great many, always in a ball shape of loose or tight, sparse or dense flower clusters. The leaves of only a few smell like onions - normally only when bruised. With over 300 species to choose from, the allium group is a popular choice for the spring garden.
About this Variety
Allium giganteum, commonly called giant onion, is perhaps the tallest of the ornamental onions. It is a bulbous perennial that produces a basal rosette of grayish-green, strap-shaped leaves. From the center of each basal rosette rises a thick, naked, 3-4' tall scape (stem) which is topped in late spring by a dense, globular, softball-sized, 5-6" diameter cluster (umbel) of tiny, star-shaped lilac-purple florets. Leaves and scapes smell like onions when bruised, but plant is not used for culinary purposes. Leaves begin to die back as plants begin flowering.
- Deer & critter resistant
- Beneficial to pollinators; Attracts butterflies
- Excellent for cut flowers & perfect for drying
- Drought tolerant & easy to grow
- Grows well in containers, borders, rock gardens & mass plantings; Provides winter interest after blooming
Late Spring to Early Summer
Grows 32-38" tall
Plant 6-8" apart, 4-8" deep
Grow as Perennial in zones 4-9. Grow as Annual elsewhere.
Plant in the fall, before the first frost hardens the soil. Dig a hole to the required depth. Place bulb in hole, pointed side up. Cover with soil and water thoroughly. Mulch in extreme climates. For container planting, bury the bulb three times as deep as the bulb is wide. In zones 6 and below, you will need to protect your bulb containers. Place them near the foundation of the house or other structure. In zones 3-5, place the container in an unheated garage or shed. After blooming, leave the bulbs in place so plants can clump or reseed. Divide only when containers or planting spaces become too crowded. Propagate in the fall by division after they have been chilled for four weeks in a moist medium.
Allium does not like 'wet feet'. Be sure to plant in a sunny location where the soil drains well. The bulbs will rot in wet areas. Dig, divide and replant bulbs after a few years of decreasing flower production.