perennial

Thunberg's Ornamental Onion

Allium thunbergii

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Thunberg's Ornamental Onion (Allium thunbergii) at County Line Nursery

Thunberg's Ornamental Onion flowers

Thunberg's Ornamental Onion flowers

(Photo courtesy of NetPS Plant Finder)

Thunberg's Ornamental Onion (Allium thunbergii) at County Line Nursery

Thunberg's Ornamental Onion in bloom

Thunberg's Ornamental Onion in bloom

(Photo courtesy of NetPS Plant Finder)

Plant Height:  8 inches

Flower Height:  15 inches

Spread:  12 inches

Sunlight:  full sun  partial shade 

Hardiness Zone:  4a

Other Names:  Thunberg's Chive, Japanese Onion

Description:

Interesting lavender clusters of nodding flowers emerge from narrow strappy dark-green foliage late in the season; attracts butterflies; plant close together for a massed effect

Ornamental Features

Thunberg's Ornamental Onion is blanketed in stunning lightly-scented nodding lavender bell-shaped flowers at the ends of the stems from early to mid fall. The flowers are excellent for cutting. Its fragrant narrow leaves remain green in color throughout the season.

Landscape Attributes

Thunberg's Ornamental Onion is an open herbaceous perennial with tall flower stalks held atop a low mound of foliage. It brings an extremely fine and delicate texture to the garden composition and should be used to full effect.

This is a relatively low maintenance plant, and should only be pruned after flowering to avoid removing any of the current season's flowers. It is a good choice for attracting butterflies to your yard, but is not particularly attractive to deer who tend to leave it alone in favor of tastier treats. It has no significant negative characteristics.

Thunberg's Ornamental Onion is recommended for the following landscape applications;

  • Mass Planting
  • Rock/Alpine Gardens
  • Border Edging
  • General Garden Use
  • Groundcover
  • Herb Gardens
  • Container Planting

Planting & Growing

Thunberg's Ornamental Onion will grow to be about 8 inches tall at maturity extending to 15 inches tall with the flowers, with a spread of 12 inches. It grows at a medium rate, and under ideal conditions can be expected to live for approximately 5 years. As an herbaceous perennial, this plant will usually die back to the crown each winter, and will regrow from the base each spring. Be careful not to disturb the crown in late winter when it may not be readily seen!

This plant does best in full sun to partial shade. It does best in average to evenly moist conditions, but will not tolerate standing water. It is not particular as to soil type or pH, and is able to handle environmental salt. It is highly tolerant of urban pollution and will even thrive in inner city environments. This species is not originally from North America. It can be propagated by division.

Thunberg's Ornamental Onion is a fine choice for the garden, but it is also a good selection for planting in outdoor pots and containers. It is often used as a 'filler' in the 'spiller-thriller-filler' container combination, providing a mass of flowers against which the larger thriller plants stand out. Note that when growing plants in outdoor containers and baskets, they may require more frequent waterings than they would in the yard or garden.

 
 
Hardiness Zone Plant Height Minimum Sunlight
Characteristics
Massing  Rock  Edging  Garden  Groundcover  Herb  Container 
Applications
Flowers  Texture  Plant Form  Attracts Wildlife 
Ornamental Features