The Plant Guide

Browse the Full Plant Guide

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.

Fine Gardening Recommended Products

Dramm Revolution Adjustable 9-Pattern Metal Hose Nozzle

Fine Gardening receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

- 15 x 10 x 7 inches
- Ergonomic insulated grip
- Maximum pressure of 90 PSI
- Fully adjustable spray pattern
- No trigger lock
Buy at Amazon

Lee Valley Mini Garden Shear Set

Fine Gardening receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

These shears have a distinctive finger rest that not only aids grip but allows greater freedom of movement than a conventional handle design. They have a durable powder-coat finish to resist rust and wear, and a simple clasp that locks the spring-action stainless-steel blades closed. The set includes one pair of round-nose shears measuring 5 1/2" overall with 1" blades for cutting stems up to 3/8" in diameter, and one pair of 6 1/2" needle-nose shears with 2" fine-tip blades for precise work.
Buy at Lee Valley

Dramm 17050 50′ ColorStorm 1/2″ Standard Soaker Hose

Fine Gardening receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

- Provides sufficient amounts of water to the garden without the hassle of hand watering
- Conveniently waters garden and beds
- 50 ft. by 1/2 inch diameter made from recycled material; lifetime guarantee
- Made in the USA
Buy at Amazon
  • 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

Plant Characteristics are only available to Fine Gardening members

Sign up for a free trial and get instant access to our complete plant guide as well as our entire collection of articles and videos.

Start Free Trial

Already a member?

X

Related Plants

Related Articles

More From the Plant Guide

Search our database of 1738 Plants

Winter Interest

Partial Shade

Browse the Full Plant Guide

Fine Gardening Magazine

Fine Gardening – Issue 222
February Does Have a Purpose After All | Letter from the Editor
Fine Gardening – Issue 221
Tips for Upcycling Garden Trash into Useful Tools
Fine Gardening – Issue 220
End-of-Season Regrets | Letter from the Editor
Fine Gardening – Issue 219
All Gardens Have Teachable Moments | Letter from the Editor
Fine Gardening

Follow

Newsletter

Membership & Magazine

Taunton Network

© 2025 Active Interest Media. All rights reserved.

Fine Gardening receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.