10 Varieties of Purple Allium

There are many hundreds of species in the Allium genus, including the edible vegetable type we know as onions, chives, and leeks. But there are many alliums that work well as ornamental plants, often known as "ornamental onions" or "flowering onions." These plants grow from bulbs, like spring tulips and daffodils, but alliums typically bloom a bit later than the spring bulbs, beginning in late spring and flowering well into summer. The appeal of alliums is not in the foliage, which tends to be rather sparse and grass-like, but in the colorful flower clusters that perch atop tall stalks Usually roughly spherical in shape, these umbels of tiny star-shaped flowers appear as ethereal balls of color in the garden, magically floating above the other plants.

Grow ornamental onions in full sun and in soil that drains well. They need an adequate amount of moisture consistently, but their bulbs do not like to be waterlogged. Since they perform better in fertile ground (they like plenty of nitrogen), mix plenty of compost into the soil. After blooming, let the foliage die back of its own accord (and remember to water the plants during this period). They are deer-resistant, as well as being rabbit-proof flowers; even rodents leave them alone.

Here are 10 types of allium in a wide range of light to dark purple hues to consider for your garden.

Gardening Tip

In the case of alliums, the importance of using companion plants goes beyond color combinations. Since the leaves of flowering onions become less and less attractive as the season wears on, it is advisable to hide them. Companion plants can do just that. Use bigger companion plants to achieve this end when you are dealing with the bigger alliums.


Here is another factor to consider when deciding upon suitable companions: plant texture. The coarse flower head of an allium such as Ambassador will contrast nicely with the more delicate flowers of, say, Six Hills Giant catmint.

  • 01 of 10

    Ornamental Onion (Allium atropurpureum)

    Allium atropurpureum

    The Spruce / David Beaulieu

    While many purple alliums are hybrid plant, this is a pure species. Allium atropurpureum is perhaps the darkest purple allium. Its flowers have enough of a touch of red in them to be called "wine-purple" or "maroon-purple." Color is, in fact, the main draw in growing this type of flowering onion, as the blooms are small compared to many hybriid alliums. The size of the flower head, which forms not a full globe (sphere) but a half globe, is just 2 1/2 inches.

    Native Area: Hungary, Turkey

    USDA Growing Zones: 4–8

    Height: 2–3 feet

    Sun Exposure: Full sun

  • 02 of 10

    Allium 'Ambassador'

    Allium Ambassador flower

    The Spruce / David Beaulieu

    A. 'Ambassador is a mauve-purple variety. When the flower buds are still tight, the globe perched atop the sturdy stalk measures about 5 1/2 inches. But soon, the individual flower stems start to peel off from the center, the buds fully open, and—lo and behold—the diameter of the flower head increases to an impressive 7 inches. It is fun to watch this transformation.

    'Ambassador', like many allium varieties, is a hybrid cross of several native allium species.

    Native Area: Nursery hybrid

    USDA Growing Zones: 4–8

    Height: 3–4 feet

    Sun Exposure: Full sun

  • 03 of 10

    'Globemaster' (Allium 'Globemaster')

    Globemaster allium flower

    The Spruce / David Beaulieu

    With a name like 'Globemaster,' this type of hybrid allium clearly claims to be the poster child for the ornamental onions that display spherical flower heads. The fact that its flowers are densely packed (thus forming a tight ball) lends some credence to this claim since it gives the flower head the appearance (from a distance) of a solid ball, rather than a collection of smaller flowers (which is what it actually is).

    'Globemaster' alliums should be their biggest in year one, bearing flower heads that are 8 inches across. After that first year, they downsize, both in terms of the flower heads and overall plant height.

    Native Area: Nursery hybrid

    USDA Growing Zones: 5–8

    Height: 18–30 inches

    Sun Exposure: Full sun

  • 04 of 10

    'Purple Sensation' (Allium hollandicum 'Purple Sensation' )

    Alliums in a fern bed

    The Spruce / David Beaulieu

    If the name of 'Globemaster' suggests a plant with big ideas about its standing amongst alliums with globe-shaped flower heads, then A. hollandicum 'Purple Sensation' would seem to bound and determined to be at the head of the class in terms of displaying a purple color. The deep lavender flowers are about 4 inches across, blooming in May and June, before most of the large-flowering alliums.

    Native Area: Iran and Kyrgyzstan 

    USDA Growing Zones: 4–10

    Height: 24–32 inches

    Sun Exposure: Full sun

    Continue to 5 of 10 below.
  • 05 of 10

    Blue Allium (Allium careleum, Allium azureum)

    Azure alliums popping up through peony foliage

    The Spruce / David Beaulieu

    Here is another factor to consider when deciding upon suitable companions: plant texture. The coarse flower head of an allium such as Ambassador will contrast nicely with the more delicate flowers of, say, Six Hills Giant catmint.

    There are two allium species that carry the common name "blue allium": Allium caeruleum and Allium azureum. Both plants have relatively small 1 1/2-inch flowers in a purplish-blue hue. They bloom in late spring and early summer, well before the large-flowering alliums.

    Native Area: Central Asia

    USDA Growing Zones: 4–10

    Height: 14–20 inches

    Sun Exposure: Full sun

  • 06 of 10

    Giant Onion (Allium giganteum)

    Giant allium
    Simoni/Shutterstock

    Although giganteum means "giant," it is to plant height (namely, 4 to 5 feet), not to flower-head diameter (which, at 5 inches, is smaller than that for both Globemaster and Ambassador) that the moniker refers.

    Native Area: Central and Western Asia

    USDA Growing Zones: 5–8

    Height: 3–5 feet

    Sun Exposure: Full sun

  • 07 of 10

    Star of Persia (Allium cristophii)

    Blooms of Allium chrisophii which have self seeded along a garden path.
    Allium christophii with its 30 - 40 cm wide heads of flowers is a great candidate for 'fireworks' in an outdoor fairy garden. Photo © 2013 Lesley Shepherd

    Allium christophii, produces large, spherical balls of tiny pale lavender flowers that resemble exploding fireworks. The flowers heads are among the largest of all alliums, at up to 12 inches in diameter. The blooms hold their shape well, often lasting in mid summer.

    Native Area: Iran, Turkey, central Asia

    USDA Growing Zones: 4–8

    Height: 1–2 feet

    Sun Exposure: Full sun

  • 08 of 10

    Tumbleweed Onion (Allium schubertii)

    Schubert's Allium flower

    The Spruce / David Beaulieu

    The plants grow to be 18 to 24 inches tall at maturity and are listed for zones 5 to 8.

    It's a reach to call this a purple allium, since the small flowers are more accurately alled pink. But the attraction here is the size and shape of the flower head, not its color. The irregular shape of the 18-inch flower head gives it the appearance of fireworks that have just exploded. It shares this quality with A. cristophii.

    The plants grow to be 18 to 24 inches tall at maturity and are listed for zones 5 to 8.

    Native Area: Eastern Mediterranean and Central Asia

    USDA Growing Zones: 5–8

    Height: 1–2 feet

    Sun Exposure: Full sun

    Continue to 9 of 10 below.
  • 09 of 10

    'Early Emperor' (Allium 'Early Emperor')

    'Early Emperor' has a somewhat looser flower head of rich purple flowers that appear in May, before most of the other tall alliums.

    Native Area: Nursery hybrid

    USDA Growing Zones: 5–7

    Height: 2–4 feet

    Sun Exposure: Full Sun

  • 10 of 10

    'Gladiator' (Allium 'Gladiator')

    'Gladiator' is among the most statuesque of the purple-flowering hybrid alliums, with sturdy 3- to 4-foot stalks supporting 6-inch flower heads that are densely packed with tiny start-shaped flowers. This award-winning plant blooms in late spring and early summer.

    Native Area: Nursery hybrid

    USDA Growing Zones: 3–8

    Height: 3–4 feet

    Sun Exposure: Full sun