The new Jolt dianthus has been excellent in LSU AgCenter plant trials. (Photo by Allen Owings, LSU AgCenter)

Amazon Rose Magic dianthus, a top cool-season bedding plant in Louisiana, is a Louisiana Super Plant. (Photo by Allen Owings, LSU AgCenter)

News Release Distributed 11/06/15

By Allen Owings 
LSU AgCenter horticulturist

HAMMOND, La. – November is prime time for cool-season bedding plants, and dianthus have been among the plants in this group gaining considerable popularity the past 10-15 years. Pansies have long been the most popular cool-season bedding plant, but many new dianthus varieties are making this great, under-used cool-season flower better known to home gardeners.

The Telstar series of dianthus is a recommended group for Louisiana. Individual plants reach 12 inches tall and bear clove-scented flowers that are about an inch and a half across. Numerous flower colors are available in the series, and you can depend on success whether you choose to use them in a landscape bed or container.

The Amazon series is a selection in the LSU AgCenter Louisiana Super Plants program. These were developed by PanAmerican Seed Company by crossing Dianthus chinensis with Dianthus barbatus to create an interspecific hybrid. The results are nothing short of outstanding.

Louisiana Super Plants have exceptional characteristics and performance in Louisiana growing conditions, and the Amazon dianthuses really deserve this tribute. The foliage is an unusually rich, deep green, and the narrow leaves form a mound at the base. Even when out of bloom, they provide a verdant green color in the winter landscape.

The stocky flower stalks of Amazon dianthus are clothed in narrow green foliage, rise about 2 feet above the basal growth and produce large clusters of colorful flowers. However, unlike older varieties of dianthus (sometimes called sweet William), the plants do not have to go through winter cold to trigger flowering.

The three colors included in the Amazon series – Neon Purple, Neon Cherry and Rose Magic –are brilliant and eye-catching. Neon Purple and Neon Cherry practically glow, their colors are so intense and vivid. Planted together, the colors seem to vibrate visually. You can buy each color separately and plant them together or buy them in a combination called Neon Duo.

Amazon Rose Magic is the favorite of most folks. The large clusters of flowers go through a remarkable, yes “magical,” transformation as they bloom. The flowers open a bright white, age to a soft pink and finally finish up an intense rose. All three colors appear simultaneously in each cluster of flowers. Combine Rose Magic with blue, lavender, pink, silver and white flowers for an elegant effect in the garden or in containers.

The tall -rowing Bouquet series and the bicolor bloomer Corona Cherry Magic dianthus are also popular and are good landscape plants you can try across all of Louisiana. A new cousin to the Amazon dianthus is the Jolt series, with pink- and cherry-blooming varieties. Jolt Pink was one of the top performing new bedding plant varieties in 2015 trials at the LSU AgCenter Hammond Research Station. You may also want to try the Dash series of dianthus.

Dianthus perform best in full sunlight but also do well in some filtered afternoon shade. Soil in landscape beds needs to be loose, well-drained and fertile. Dianthus do well at a slightly acid to slightly alkaline soil pH. They do not tolerate wet soil conditions, so it is important to adequately prepare a landscape bed and irrigate properly.

Plant dianthus in fall on a 10- to 12-inch spacing to achieve a full landscape effect. At planting, or shortly thereafter, broadcast an application of a slow-release fertilizer over the entire bed area. Depending on plant performance, a second, light application may be beneficial in early spring.

Dianthus usually last well until mid- to-late May in Louisiana and can even grow and bloom through summer with limited success. Although dianthus are perennial, they likely will perform best when treated as an annual, cool-season plant from mid-fall through late spring.

You can see more about work being done in landscape horticulture by visiting the LSU AgCenter Hammond Research Station website. Also, like us on Facebook. You can find an abundance of landscape information for both home gardeners and industry professionals at both sites.