Regions / Middle South
Selecting plants suited to the Middle South climate is a key step to success.
Various initiatives have taken place to determine how well plants would withstand the cold winter temperatures (Plant Hardiness Zones) or when plants would start suffering from the heat (Plant Heat Zones).
The Middle South region lies in USDA Plant Hardiness Zone 7 and in AHS Heat Zones 3 through 8.
Tall and majestic, Allium 'His Excellency' is a most architectural flowering onion with its large globe-shaped inflorescence, 5 in. across (12 cm), densely packed with hundreds of small, star-shaped violet-blue flowers. Blooming for weeks in late spring to early summer, this spectacular Allium remains ornamental in the garden well into summer. Planted in groups, it makes a terrific focal point within the border.
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.
Allium 'Summer Beauty' is a bulbous perennial with charming, rounded umbels, 2 in. across (5 cm), packed with up to 30 soft lavender-pink, bell-shaped flowers. Blooming in mid- to late summer, the luminous flowers are borne on sturdy, upright stems above a foliage of onion-scented, strap-shaped leaves, which remains attractive all season long.
Allium amplectens 'Graceful Beauty' (Ornamental Onion) is a hardy perennial bulb featuring globe-shaped flowerheads, up to 3 in. across (7 cm), packed with 10 to 50 starry white florets adorned with lavender stamens and purple anthers. Blooming in late spring to early summer, this particularly pretty Allium enjoys long-lasting blooms and remains ornamental in the garden well into summer.
Allium atropurpureum is a hardy perennial bulb with star-shaped, deep purple-red flowers packed into a half-globe umbel, 2 in. wide (5 cm). Each flower is comprised of deep merlot-purple florets adorned with blueberry-purple eyes, which creates a wonderful contrast of colors. Blooming in late spring to early summer, the flowers are borne on sturdy, upright stems above strap-shaped green leaves.
A favorite of many gardeners, multiple award-winner Allium 'Purple Sensation' is a striking ornamental onion with its inflorescence consisting of dozens of small, star-shaped, rich violet-lilac flowers, forming perfectly round flowerheads, 3 in. wide (8 cm). They are borne atop sturdy stalks, which arise from a group of 6 to 8 handsome, blue-green, straplike leaves.
An unusual, ivory-white dwarf ornamental onion, Allium karataviense 'Ivory Queen' (Turkestan Onion) is quite attractive with its elegant globe-shaped clusters, 5 in. wide (12 cm), of starry white flowers nestled in a beautiful foliage consisting of wide and recurved, gray-green leaves, slightly red edged. A very ornamental ensemble!
Allium oreophilum (Pink Lily Leek) is a compact, hardy bulb with delicate, loose umbels of rosy reddish-pink, star-shaped flowers adorned with darker midveins. The blossoms are mounted on wiry gray-mauve stems and rise above narrow, semi-erect, gray-green leaves.
Blooming about two weeks earlier than the other large Alliums, Allium rosenbachianum (Showy Persian Onion) is a bulbous perennial with large, rounded umbels, 4 in. across (10 cm), packed with up to 50 deep-purple, star-shaped flowers adorned with prominent, white stamens.