Japanese onion (Allium thunbergii) AL-ee-um thun-BER-jee-eye Genus:  Allium This is the last of the ornamental onions to flower, when mop-like heads of rose-purple flowers appear with orange anthers. The flowers are impervious to frost or snow. Superior cultivars include ‘Ozawa’, with larger purple flower heads than the species. A white-flowered form known as A. thunbergii ‘Alba’ is a splendid plant, with cup-shaped florets sporting white stamens, yellow anthers, and green centers. Care:  Provide full sun to part shade and average, well-drained soil. Propagation:  Sow seed in spring in containers or in situ. Divide clump-forming  plants in spring. Problems:  Bulb rot in damp conditions. Onion fly and thrips.

Overview

Height 6 in. to 12 in. Light Full Sun to Part Shade Moisture Medium Moisture Maintenance Low Characteristics Attracts Butterflies, Attracts Hummingbirds, Fragrant Foliage Bloom Time Fall, Late Summer, Summer Flower Color Purple, Red Uses Beds and Borders, Naturalizing Style Rock Garden Seasonal Interest Summer Interest Tolerance Deer Tolerant