Gardening Laidback Gardener Tip of the Day Perennials

Allium ‘Millenium’: The 2018 Perennial of the Year

20180602A Perennial Plant Association
Allium ‘Millenium’. Source: Perennial Plant Association

The Perennial of the Year program, organized by the Perennial Plant Association, has come up with some truly stupendous plants over the years. Almost every past winner has quickly become a classic in the field of temperate climate perennials. Just think of a few past winners, such as ‘Jack Frost’ brunnera (Brunnera macrophylla ‘Jack Frost’, 2012), Rozanne geranium (Geranium ‘Gerwat’, 2008), ‘Karl Foerster’ feather reed grass (Calamagrostis x acutiflora ‘Karl Foerster’, 2001) or ‘Goldsturm’ coneflower (Rudbeckia fulgida sulllivanti ‘Goldsturm’, 1999). Many experienced gardeners will recognize the names instantly and even if you don’t, you almost certainly grow them in your garden. They’re everywhere!

And that’s probably what will happen with the 2018 winner, Allium ‘Millenium’. This plant, developed by allium guru Mark McDonough, has it all, beauty, ease of care, good availability, even edible flowers and leaves.

Onions and Garlic

The genus Allium, with over 750 species distributed throughout the northern hemisphere, is extremely varied. The edible varieties are best known and include onions (A. cepa), garlic (A. sativum) and leeks (Allium ampeloprasum), but there are also many spring-flowering ornamental bulbs, such as giant onion (A. giganteum), with its huge globe of purple flowers. ‘Millenium’, however, is more closely related to its smaller cousin, chives (A. schoenoprasum), because it doesn’t form a proper bulb, but instead a dense clump of leaves with fibrous roots.

Allium ‘Millenium’. Source:

‘Millenium’ has a long period of interest. Its dark green upright leaves, flat and linear, create a beautiful tuft of green in earliest spring, like an ornamental grass, well before flowering begins in July. The flowers, purple-pink balls about 2 inches (5 cm) in diameter, bloom for about a month in the middle of the summer and are lightly scented. No, they do not smell like onions, but foliage does if you bruise it.

The flowers attract pollinating insects, such as bees and butterflies, but the foliage has a bit of a repellant effect, so mammalian herbivores, such as deer and rabbits, leave it alone. Nor does it seem subject to insect pests. Since the flowers are nearly sterile, there are no unwanted seedlings and no risk the plant will become invasive.

‘Millennium’ grows to about 16 to 20 inches (40 to 50 cm) in height and 12 to 18 inches (30 and 45 cm) in diameter. It’s easy to multiply by division, which you can do in spring or fall.

The ‘Millenium’ Story

Allium ‘Millenium’. Source:

Massachusetts ‘Millenium’ allium breeder Mark McDonough has been an avid collector of alliums for almost 40 years. He has thousands of species and cultivars in his collection and makes dozens of controlled crosses each year. But alliums interbreed readily, creating their own hybrids, and ‘Millenium’ is one of the self-sown hybrids resulting from a bit of allium hanky-panky. Although he recognizes in ‘Millenium’ genes of A. nutans and A. lusitanicum, McDonough can’t trace the plant’s real parents with any certainty.

As the name suggests, ‘Millenium’ (sometimes misspelled ‘Millennium’, but it was registered spelled with one “n”) was launched in 2000 and has enjoyed fantastic popularity, to the point where it is already one of the best-selling ornamental alliums in the world. You ought to be able to find it in any garden center in areas where it can be grown and, if not, a quick search on the Internet will lead you to mail order sources.

Easy to Grow

Plant allium ‘Millenium’ in full sun in fairly rich, well-drained soil. If your soil is heavy clay or soggy, you’d do better to grow it in a container or raised bed. ‘Millenium’ is quite drought-tolerant once established and makes an excellent cut flower. As for its hardiness, it’s a plant for temperate climates with cool to cold winters, from zones 3 to about 8. (I’ve seen it listed in some texts as only hardy from zone 5 and up, but I can assure you it does wonderfully in zone 3.)

Allium ‘Millenium’: a perennial to discover absolutely this summer!

Garden writer and blogger, author of 65 gardening books, lecturer and communicator, the Laidback Gardener, Larry Hodgson, passed away in October 2022. Known for his great generosity, his thoroughness and his sense of humor, he reached several generations of amateur and professional gardeners over his 40-year career. Thanks to his son, Mathieu Hodgson, and a team of contributors, will continue its mission of demystifying gardening and making it more accessible to all.

1 comment on “Allium ‘Millenium’: The 2018 Perennial of the Year

  1. Pingback: ¿Allium Millenium es invasivo? - Gardenun

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