Allium, aka 'Ornamental Onion'

Allium's amazing purple balls of color burst onto the scene in The Big Little Garden in spring of 2018. Dozens of 'Miami', 'Mars', 'Purple Sensation', Firmament', 'Flavum', and 'Graceful' bulbs had been planted in the fall of 2017, adding to an earlier experimentation with the varieties 'Christophii' and 'Sphaerocephalon'.  Hours of planting effort and the long winter wait were well rewarded. Allium of different varieties bloomed from May until August, adding color, texture and interest. Visitors often ask, with a smile, "what are those big purple balls floating in the garden?"

Allium bulbs are planted in the fall along with tulip and daffodil bulbs and are available in many colors, shapes and sizes. In my garden, purple is the dominant theme, with blooms ranging from golf ball to volleyball size! Lesser known varieties sport yellow, white, pink and even blue blooms.

A major design feature is that allium can be planted very close to and in between perennials and other bulbs. Strappy foliage usually lays close to the ground and is quickly covered by the foliage of adjacent plants. This allows the foliage to die back naturally and undetected, hence fueling the bulb for next season's bloom. An added benefit is that once the color and flower petals fade, the "skeleton" remains as a beautiful dried orb for use indoors in a vase or to decorate a book shelf.

  • Plant type: bulb, native to the US (plants may re-seed, but are unlikely to bloom for at least 3 years)

  • Growing Conditions: full to part sun; dry, well-drained soil

  • Size: from 6" to 5', depending upon variety

  • Spread: Non-invasive, single bulbs are slow to divide, some varieties may re-seed

  • Bloom: late-May to mid-August in Zone 5b

  • Maintenance: minimal foliage which dies back quickly, no need to deadhead

  • Biodiversity: popular with all types of bees & butterflies

  • Pairings: plant among daylilies, grasses, geum, astilbe, persicaria, veronicastrum

  • Location: plant tightly throughout garden beds so blooms emerge among all other specimens

  • Pests: none, and their onion-y aroma actually helps deter deer and rodents from the garden

  • Sourcing: available through The Big Little Garden

june 9th: allium 'miami' in the mailbox garden

The purple orbs of allium contrast beautifully with the creamy spikes of Eremurus (foxtail lily) and flat heads of yellow achillea.

june 2nd: allium 'purple sensation' in west garden

The fireworks begin early with Allium interplanted among Daylilies, Amsonia, Knapweed and Achillea. A later blooming variety 'Miami' is seen in bud in the foreground (lower left) and in the middle of the image above. Receives afternoon sun.

mid-june: mixed border in west garden, part sun/shade

mid-june: mailbox garden with allium 'miami', full sun

Three different varieties of tall allium can be seen in this bed in various stages of bloom: ‘Persian Blue’, ‘Miami’ and ‘Purple Sensation’. A few weeks later, they will be joined by ‘Gladiator’ and ‘Mediterranean Bells’.

Allium can be a useful solution for awkward planting areas. Three different varieties with staggered bloom time are seen here curbside, emerging from low growing sedum underneath the mailbox. Dried seed heads will remain well after frost.