‘Millenium’ ornamental onion

Story by Russell Studebaker

The Perennial Plant Association chose Allium ‘Millenium’ as the 2018 Perennial Plant of the Year. This herbaceous perennial and relative of the garden onion was bred by Mark McDonough, horticulture researcher from Massachusetts, and introduced by Plant Delights Nursery in Raleigh, N.C., in 2000. 

‘Millenium’ (yes, the name was registered with one “n”) reaches 10-15 inches tall and offers many desirable landscape qualities in addition to its uniform habit and shiny green foliage, such as its masses of rosy purple 2-3-inch spherical umbels that last as long as four weeks. In addition to its drought tolerance, no serious pest problems have been reported and deer and rabbits leave it alone.

Unlike other Allium, ‘Millenium’ produces 50 percent less seed, therefore self-sowing less than its relatives. It is easily propagated by division in spring or fall. 

This low-maintenance perennial adds much to a landscape, flowering when the garden seems to most need color, and even better, attracting butterflies, bees, and other pollinators.

Quick Facts and Keys to Success
Common Name: ‘Millenium’ ornamental onion
Botanical Name: Allium ‘Millenium’
Type: Herbaceous perennial 
Exposure: Best performance in full sun; appreciates partial or afternoon shade in hot climates.
Flowers: 2-3-inch round flower heads of rose purple florets. Can be used for cut flowers.
Foliage: Clump-forming; grass-like; deep green; 10-15 inches tall
Soil: Well drained; drought resistant once established
Maintenance: Cut back foliage in the fall.
In Your Landscape: This is a butterfly, bee, and pollinator magnet. Plant en masse, or for contrast, pair with shorter goldenrods (Solidago spp.). Complements the silver foliage of Russian sage (Perovskia atriplicifolia) and the blue flowers of downy skullcap (Scutellaria incana).

Photo: ‘Millenium’ is a low-maintenance perennial that attracts pollinators and adds long-lasting color to the midsummer garden. Photo courtesy of Walter’s Gardens, Inc., (waltersgardens.com).

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