Southgate rhododendron in bud at the Hammond Research Station. (Photo by Allen Owings. Click on photo for downloadable image.) Southgate Brandi (Photo courtesy of Southern Living Plants. Click on photo for downloadable image.) News Release Distributed 02/01/13
By Allen Owings
LSU AgCenter horticulturist
HAMMOND, La. – A couple years ago saw the debut of a new, heat-tolerant group of rhododendron varieties from the Southern Living Plant Collection. These were developed to perform well in the Deep South while performing equally well in traditional rhododendron areas.
The Southgate rhododendron hybrids bloom in early April in south Louisiana and were developed by retired veterinarian and longtime plant breeder Dr. John Thornton of Franklinton, La. Wholesale production has increased, and we are approaching spring bloom time for these great plants.
Dr. Thornton began his rhododendron breeding efforts in the early 1970s. He is widely known among azalea and rhododendron enthusiasts for his vast knowledge of these plants and breeding techniques that have long been investigated to improve the species. Much of his work has been with the R. hyperythrum species.
Southgate Brandi features deep pink buds that open to pink, ruffled blooms with a dense habit and dark green, recurved, glossy leaves.
Southgate Breezy sports medium-pink buds that open to white with a prominent maroon blotch and a medium-dense habit with medium-green leaves.
Southgate Radiance showcases deep lavender buds that open to light purple and has a medium-dense habit.
Southgate Divine has light-pink buds opening to white with purple specks and has a medium-dense habit with medium-green leaves.
Southgate Grace has deep pink buds that open white, a dense habit and recurved leaves.
Southgate Breezy, Radiance and Divine all grow to 4 feet tall by 5 feet wide in 10 years, while Brandi grows to 3 feet tall by 4 feet wide. Grace reaches 4 feet tall by 6 feet wide in a decade.
Rhododendrons require cultural conditions similar to azaleas. This includes shade during portions of the day, especially early to late afternoons. The soil pH required for optimum growth is 5.5. Soils need to be enriched with organic matter, and it is important to plant rhododendrons in raised beds. Mulch them with pine straw and maintain uniformity in soil moisture for best success.
Do not plant them too deep but slightly higher than the plants were growing in the containers.
You can see more about work being done in landscape horticulture by viewing 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.
Rick Bogren