Robin Hill azaleas include new Louisiana Super Plant

Richard Bogren, Owings, Allen D.  |  10/6/2012 12:11:19 AM

A unique feature of Conversation Piece azaleas is that flowers of different colors appear on the same plant. (Photo by Allen Owings. Click on photo for downloadable image.)

News Release Distributed 10/05/12

By Allen Owings
, LSU AgCenter horticulturist

Encore azaleas have gathered considerable attention over the past 10 years, but we need to remember we had great, fall-flowering – sometimes referred to a multi-seasonal-flowering – azaleas before the Encore varieties. An example is the Fashion azalea variety. But another azalea group widely planted in Louisiana for fall blooming are the Robin Hill hybrids.

These azaleas resulted from hybridization work conducted by Robert Gartrell, of New Jersey, in the 1950s and 1960s. These have large flowers on hardy plants, good form and foliage, and an intermediate growth size. Other main attributes are cold hardiness and an extended blooming season.

Most years, Robin Hill azalea varieties will bloom for six months in Louisiana. You can get two to three months of bloom in spring and another three to four months in late summer through early winter. This group includes 70 varieties with 10-12 readily available in Louisiana. Louisiana nursery growers began growing these popular azaleas in the 1980s, and they continue to be used around the state today.

The most popular and widely sold variety of Robin Hill azalea in Louisiana is Conversation Piece. It has been named our first LSU AgCenter Louisiana Super Plant for this fall.

Flowers on Conversation Piece can be nearly 4 inches across. A unique feature of Conversation Piece is that flowers of different colors appear on the same plant. Flower colors range from dark pink to nearly white to variegated pink and white with darker pink center blotches on the same plant. Flowering occurs in fall and again in spring.

Plants grow 3 feet to 5 feet tall by 3 feet to 5 feet wide. You can use this low-growing, mounding evergreen shrub as a color accent or in a foundation planting in partly shaded areas.

For best azalea results in Louisiana, plant them in fall. Conversation Piece azaleas need to be planted 4 feet apart, and we suggest planting in groups of 3, 5 or 7 plants. Azaleas like partial sun to partially shaded locations and need well-drained, raised beds with moderately acid soil. Irrigate once to twice weekly when rainfall is lacking. Prune within two to four weeks after any bloom cycle is completed, and fertilize only in spring after blooming with a slow-release fertilizer.

Other similar varieties of these azaleas for Louisiana include Watchet, Nancy of Robin Hill, White Moon, Dorothy Rees, Roddy, Gwenda, Sir Robert and Sherbrook. Flower colors vary from white to pink, blush, bicolors and more. The newest variety is Freddy, a beautiful white-flowering sport of Watchet. It, however, is limited in availability for home gardeners right now. Some other, under-appreciated varieties of Robin Hill azaleas are Hilda Niblett and Talbot.

Intermediate-growing azaleas, like Robin Hill varieties, work well in foundation plantings with Knock Out roses, Indian hawthorn, loropetalums and other popular shrubs. They are also great for use in beds underneath trees as a companion plant with hydrangeas and native shrubs. Including small-growing trees, such as redbuds and Japanese magnolias, add appeal to an azalea planting, and a Japanese maple goes great in an azalea garden as a smaller, signature, focal tree.

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

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