From the Himalayan foothills comes one of the garden's most arresting vertical accents. Allium giganteum builds slowly underground through late winter, then launches bare stems skyward in late spring — sometimes reaching six feet — while its gray-green basal leaves, smelling faintly of onion when brushed, begin their inevitable decline. The flowers arrive at the summit: dense, perfectly spherical umbels packed with dozens of small, six-petalled florets in a rich mauve-pink that holds its color well even as it dries on the stem.

Plant the bulbs in autumn at eight inches depth, in groups of five to nine toward the back of a sunny border. The spent flower heads persist attractively through summer, turning papery and bronze as daylilies and ornamental grasses grow up around the bare stems below. It is deer-resistant and draws butterflies reliably through its brief two to three week bloom. Taller specimens may need gentle staking in exposed gardens; in sheltered spots, the stems stand firm and straight, exactly as they should.