Alliums, also known as ornamental onions, are some of the most beautiful flowering bulbs for the spring and summer garden. Plant some of these popular varieties and they'll reward you with stunning blooms that resemble fireworks frozen in time.
Persian Blue Allium
One of the most common species of ornamental onion, Persian blue (Allium aflatunense) produces a four- to five-inch ball of vivid purple-blue flowers. Plant the bulbs in the fall, six to eight inches deep and about eight inches apart. This long-lasting variety attracts pollinators and is deer- and rodent-resistant.
Bloom Season: Late spring to early summer
Growing Conditions: Full sun and well-drained soil
Size: To 3 feet tall
Zones: 4-8
Purple Sensation Allium
This ornamental onion variety is a showstopper, thanks to its four- to five-inch globes of vivid purple flowers that grow on stalks up to three feet tall. Plant your bulbs in the fall, and they'll come back year after year.
Bloom Season: Late spring to early summer
Growing Conditions: Full sun to part shade in well-drained soil
Size: To 3 feet tall
Zones: 4–9
Blue Allium
Blue allium (Allium caeruleum) is a smaller ornamental onion that offers sky-blue blooms in a ball-like cluster around one inch wide. Plant the bulbs in the fall, two to four inches deep, in beds, borders, rock gardens, and meadows.
Bloom Season: Late spring to early summer
Growing Conditions: Full sun and well-drained soil
Size: To 2 feet tall
Zones: 4–8
Chives
Easily grown from seed, and popular in the kitchen for their mild onion flavor, chives (Allium schoenoprasum) have tubular, grass-like, dark green leaves that grow in dense clumps. Its clover-like clusters of pale purple flowers add a splash of color to herb gardens, but also look gorgeous grown as an ornamental in borders or container gardens.
Bloom Season: Mid to late spring
Growing Conditions: Full sun to part shade and well-drained soil
Size: To 18 inches tall
Zones: 4–8
Golden Garlic
Commonly known as golden garlic, or lily leek, Allium moly really stands out with its yellow-hued blooms. This delicate-looking rock-garden favorite is actually quite tough, tolerating hot, dry conditions well.
Bloom Season: Late spring to early summer
Growing Conditions: Full sun to part shade and well-drained soil
Size: To 15 inches tall
Zones: 3–9
Drumstick Allium
Also known as round-headed leek, drumstick allium (Allium sphaerocephalon) produces cute, reddish-purple egg-shape flower heads. Each flower head comprises a tight cluster of tiny florets that emerge deep green but mature (top to bottom) to rose-purple. It's best grown in large groups in rock gardens, beds and borders, and open woodland areas, but it also grows well in containers.
Bloom Season: Early to midsummer
Growing Conditions: Full sun and well-drained soil
Size: To 3 feet tall
Zones: 3-10
Globemaster Allium
One of the taller varieties you can find, 'Globemaster' is ornamentally grown for its spring blooms of light-purple flower heads that are typically 6 to 10 inches in diameter. This variety is an eye-catching accent in the garden, as well as a long-lasting cut flower.
Bloom Season: Late spring
Growing Conditions: Full sun and well-drained soil
Size: To 4 feet tall
Zones: 5–8
Turkistan Onion
Known for having leaves that are as beautiful as its flowers, Turkistan onion (Allium karataviense) is among the shorter ornamental Allium varieties. It works well when planted in groups in rock gardens, border fronts, containers, and window boxes. Its pink flower heads are three to six inches across, held above three- to four-inch wide gray-green leaves. 'Ivory Queen' is a white-flowered variety.
Bloom Season: Late spring to early summer
Growing Conditions: Full sun and well-drained soil
Size: To 8 inches tall
Zones: 4–8
Pink Lily Leek
Though it's a shorter, smaller ornamental onion, pink lily leek (Allium oreophilum) produces eye-catching magenta florets that form a loose flower head. It makes an especially stunning display when planted in masses. The blooms work well in fresh or dried flower arrangements.
Bloom Season: Late spring
Growing Conditions: Full sun and well-drained soil
Size: To 18 inches tall
Zones: 4–10
Star of Persia
Commonly called star of Persia (Allium cristophii), this species produces one of the largest blooms of any Allium and can have up to 100 individual flowers packed into one flower head. The light purple flower heads can reach up to 12 inches in diameter. Plant new bulbs in the fall, three to six inches deep and 10 to 12 inches apart. Star of Persia is especially nice as a fresh cut or dried flower.
Bloom Season: Late spring
Growing Conditions: Full sun and well-drained soil
Size: To 2 feet tall
Zones: 4–8
Millenium Allium
An especially long-blooming variety, 'Millenium' fills the late-summer garden with light-purple color. The two-inch-wide heads float above a mound of glossy green foliage. It's a reliable accent plant for mixed borders and cottage gardens.
Bloom Season: Late summer
Growing Conditions: Full sun and well-drained soil
Size: To 1 foot tall
Zones: 5–8
Three-Cornered Leek
The dainty, drooping white flowers of three-cornered leek (Allium triquetrum) form loose clusters on triangular stalks (hence its common name). It grows well with roses, carrots, beets and chamomile, but it can actually prevent legumes from thriving, so steer clear of that pairing.
Bloom Season: Late spring
Growing Conditions: Sun or shade and moist, well-drained soil
Size: To 18 inches tall
Zones: 3–8
Garlic Chives
If you're looking for an edible white allium, you've found it. Also called Chinese chives, garlic chives (Allium tuberosum) bloom from late summer into fall and produce 2-inch wide clusters of white flowers. Be sure to deadhead the flowers before they set seeds to prevent the sprouting of unwanted seedlings throughout the garden.
Bloom Season: Late summer
Growing Conditions: Full sun to part shade and well-drained soil
Size: To 18 inches tall
Zones: 3-9
Hair Allium
Love it or hate it, this variety is definitely unique. Allium vineale 'Hair' produces blooms with purple centers that have green hairlike extensions. Its unusual appearance adds unique texture to beds and borders, and no doubt will be a conversation starter.
Bloom Season: Late spring
Growing Conditions: Full sun and well-drained soil
Size: To 2 feet tall
Zones: 3–8
Mount Everest
As majestic as its namesake, 'Mount Everest' offers six-inch heads of bright white flowers on tall stems. For the best visual impact, plant at least 10 to 15 bulbs in a group. 'Mount Everest' mixes beautifully with other late-spring blooming flowers, such as delphiniums, peonies, or irises.
Bloom Season: Late spring or early summer
Growing Conditions: Full sun and well-drained soil
Size: To 3 feet tall
Zones: 4–8
Nectaroscordum
Though technically not an allium, this close relative is often sold as one. Nectaroscordum siculum, commonly known as Sicilian honey garlic, produces bell-shaped flowers with reddish-purple markings. The seed heads dry well and can be used in dried flower arrangements.
Bloom Season: Late spring
Growing Conditions: Full sun and well-drained soil
Size: To 4 feet tall
Zones: 5-10
Allium senescens subsp. montanum var. glaucum
Allium senescens subsp. montanum var. glaucum has a mouthful of a name but it's perfect for the rock garden or front of the border. It has blue-green leaves that grow in a spiral and clusters of purple-pink flowers in late summer.
Bloom Season: Late summer
Growing Conditions: Full sun and well-drained soil
Size: To 6 inches tall
Zones: 5-9
Allium stipitatum
Allium stipitatum blooms in early summer with 4-inch-wide clusters of lilac flowers. It is sometimes confused with the similar showy allium.
Bloom Season: Early summer
Growing Conditions: Full sun and well-drained soil
Size: To 4 feet tall
Zones: 4-9
Showy allium
Allium rosenbachianum offers 4-inch-wide globes of purple flowers in summer.
Bloom Season: Summer
Growing Conditions: Full sun and well-drained soil
Size: To 3 feet tall
Zones: 4-10
'Summer Beauty' wild onion
Allium tanguticum 'Summer Beauty' shows off clusters of dark lavender-blue flowers in midsummer on 2-foot-tall stems.
Bloom Season: Midsummer
Growing Conditions: Full sun and well-drained soil
Size: To 2 feet tall
Zones: 4-9
