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perennial

Diadem Sweet William

Dianthus barbatus 'Diadem'

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Diadem Sweet William (Dianthus barbatus 'Diadem') at Lakeshore Garden Centres

Diadem Sweet William flowers

Diadem Sweet William flowers

(Photo courtesy of NetPS Plant Finder)

Plant Height:  15 inches

Flower Height:  20 inches

Spacing:  8 inches

Sunlight:  full sun 

Hardiness Zone:  3a

Other Names:  Perennial Sweet William

Description:

Deliciously clove-scented, velvety frilly blood-red flowers with white eyes and edges; optimal site has full sun with ample moisture; amend clay soils for best growth; seeds freely but divide for truest color

Ornamental Features

Diadem Sweet William is blanketed in stunning fragrant crimson flat-top frilly flowers with white eyes and white edges at the ends of the stems from late spring to early summer. The flowers are excellent for cutting. Its tomentose pointy leaves remain dark green in colour throughout the season.

Landscape Attributes

Diadem Sweet William is an herbaceous perennial with an upright spreading habit of growth. Its relatively fine texture sets it apart from other garden plants with less refined foliage.

This plant will require occasional maintenance and upkeep, and should only be pruned after flowering to avoid removing any of the current season's flowers. It is a good choice for attracting bees and butterflies to your yard, but is not particularly attractive to deer who tend to leave it alone in favor of tastier treats. Gardeners should be aware of the following characteristic(s) that may warrant special consideration;

  • Self-Seeding

Diadem Sweet William is recommended for the following landscape applications;

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

Planting & Growing

Diadem Sweet William will grow to be about 15 inches tall at maturity extending to 20 inches tall with the flowers, with a spread of 12 inches. When grown in masses or used as a bedding plant, individual plants should be spaced approximately 8 inches apart. Its foliage tends to remain dense right to the ground, not requiring facer plants in front. It grows at a medium rate, and tends to be biennial, meaning that it puts on vegetative growth the first year, flowers the second, and then dies. However, this species tends to self-seed and will thereby endure for years in the garden if allowed. 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 should only be grown in full sunlight. It prefers to grow in average to moist conditions, and shouldn't be allowed to dry out. It is not particular as to soil type or pH. 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 division; however, as a cultivated variety, be aware that it may be subject to certain restrictions or prohibitions on propagation.

Diadem Sweet William is a fine choice for the garden, but it is also a good selection for planting in outdoor pots and containers. With its upright habit of growth, it is best suited for use as a 'thriller' in the 'spiller-thriller-filler' container combination; plant it near the center of the pot, surrounded by smaller plants and those that spill over the edges. Note that when growing plants in outdoor containers and baskets, they may require more frequent waterings than they would in the yard or garden. Be aware that in our climate, most plants cannot be expected to survive the winter if left in containers outdoors, and this plant is no exception. Contact our experts for more information on how to protect it over the winter months.

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