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The Plant Guide

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Japanese onion

Allium thunbergii

AL-ee-um thun-BER-jee-eye

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.

CareProvide full sun to part shade and average, well-drained soil.

PropagationSow seed in spring in containers or in situ. Divide clump-forming  plants in spring.

ProblemsBulb rot in damp conditions. Onion fly and thrips.

  • Genus : Allium
  • Zones : 4, 5, 6, 7, 8, 9
  • Plant Height : 6 to 12 inches
  • Characteristics : Attracts Hummingbirds, Fragrant Foliage
  • Tolerance : Deer Tolerant
  • Bloom Time : Fall, Late Summer, Summer
  • Light : Full Sun to Partial Shade
  • Maintenance : Low
  • Moisture : Medium Moisture
  • Flower Color : Red
  • Plant Seasonal Interest : Summer Interest

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