perennial

Blue Corkscrew Onion - New For 2022!

Allium senescens 'var. glauca'

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Blue Corkscrew Onion (Allium senescens 'var. glauca') at Longfellow's Greenhouses

Blue Corkscrew Onion flowers

Blue Corkscrew Onion flowers

(Photo courtesy of NetPS Plant Finder)

Blue Corkscrew Onion (Allium senescens 'var. glauca') at Longfellow's Greenhouses

Blue Corkscrew Onion flowers

Blue Corkscrew Onion flowers

(Photo courtesy of NetPS Plant Finder)

Blue Corkscrew Onion (Allium senescens 'var. glauca') at Longfellow's Greenhouses

Blue Corkscrew Onion

Blue Corkscrew Onion

(Photo courtesy of NetPS Plant Finder)

Plant Height:  12 inches

Flower Height:  24 inches

Spread:  12 inches

Sunlight:  full sun 

Hardiness Zone:  2

Other Names:  Flowering Onion

Description:

Spiraling blue-green foliage and lavender flowers create a beautiful display in garden beds, borders or containers; foliage last throughout most of the summer months, while flowers generally bloom in late spring; deadhead after flowering to stop seeding

Ornamental Features

Blue Corkscrew Onion has masses of beautiful balls of lightly-scented lavender flowers at the ends of the stems from late spring to early summer, which are most effective when planted in groupings. Its sword-like leaves remain bluish-green in color throughout the season.

Landscape Attributes

Blue Corkscrew Onion is an open herbaceous perennial with tall flower stalks held atop a low mound of foliage. Its medium texture blends into the garden, but can always be balanced by a couple of finer or coarser plants for an effective composition.

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.

Blue Corkscrew Onion is recommended for the following landscape applications;

  • General Garden Use

Planting & Growing

Blue Corkscrew Onion will grow to be about 12 inches tall at maturity extending to 24 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! As this plant tends to go dormant in summer, it is best interplanted with late-season bloomers to hide the dying foliage.

This plant should only be grown in full sunlight. 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 is a selected variety of a species not originally from North America. It can be propagated by multiplication of the underground bulbs; however, as a cultivated variety, be aware that it may be subject to certain restrictions or prohibitions on propagation.

 
 
Hardiness Zone Plant Height Minimum Sunlight
Characteristics
Garden 
Applications
Flowers  Plant Form  Attracts Wildlife 
Ornamental Features

Disclaimer - This Plant Finder tool is an online resource representing many of the varieties that we carry over the course of the season, and is intended for informational purposes only. Inventory varies seasonally, so we cannot guarantee that every plant will be in stock at all times - please contact the store directly for current availability. It does not include our entire selection of plants, so be sure to visit our store to see varieties that may not be represented on this list.