A butterfly magnet, Allium 'Millenium' is a bulbous perennial with profuse, large, rounded umbels, 2 in. across (5 cm), tightly packed with bright rosy purple flowers. Blooming in mid to late summer, the luminous flowers are borne on sturdy, upright stems just above the attractive foliage clump of onion-scented, grass-like, glossy deep green leaves, which remain attractive all season long. The flowers are both long-lasting (up to 4 weeks) and excellent as cut flowers. This Allium is not bothered by heat and reseeding is much less a problem than in other alliums.

• 2018 Perennial Plant of the Year.
• Grows up to 15-20 in. tall (37-50 cm) and 10-15 in. wide (25-37 cm).
• Thrives in fertile, well-drained soils in full sun to part shade. Add grit to clay soils to improve drainage.  This Allium is drought tolerant.
• Lovely in beds and borders, cottage gardens, and containers. To achieve an impressive visual effect, plant in clusters.
• Known for attracting bees, butterflies, ​moths, and other pollinators, but deer ignore it.
• Generally pest and disease free.
• Cut back after flowering or merely remove dead flowerheads.

Hundreds of Allium species exist, but only a few have made a name for themselves as garden plants. The ornamental onions distinguish themselves by their remarkable diversity in color, inflorescence, and flowering height. Many species bloom in early summer - just after the spring-flowering period and just before the exuberant full bloom of summer. Certain small species are just perfect for a rock garden, and several lend themselves to naturalizing. All species can be used in the border.