Researching Roses in the Bayou State

Allen D. Owings  |  7/19/2016 2:45:43 PM

Allen Owings

Roses continue to be one of the most widely planted flowering shrubs in Louisiana. The majority of nurs­ery growers in Louisiana produce roses. These plants have a wholesale value of $10 to $15 million annually in the state.

Rose trials and evaluations have a long history in Louisiana. Notably, rose research has been conducted by the LSU AgCenter in cooperation with several partners for more than 20 years. Regional performance of roses and disease resis­tance in roses are important to grow­ers, landscapers, retailers and gardening consumers.

In Louisiana, active rose variety trials are ongoing at the AgCenter Botanic Gardens at Burden in Baton Rouge and the Hammond Research Station in Hammond, along with the Gardens of the American Rose Center in Shreveport. Typical peak spring bloom on roses is early to mid-April with fall peak bloom in October.

Finding good-performing roses in Louisiana should be a good indication of roses that will do well in other parts of the country. Louisiana has much more rainfall than other states in the south­eastern and south central United States. Every year, 65 inches of rain is common in south Louisiana, with 40-45 inches regularly occurring in north Louisiana. Climate conditions favor blackspot and Cercospora leaf spot diseases, with Cercospora being a more significant problem than many rose growers realize. Many roses that have little to no black­spot fungus problems show high suscepti­bility to Cercospora.

Current rose research and promo­tion and marketing in Louisiana include studying Earth-Kind; evaluating Easy Elegance, David Austin, Certified Roses and Kordes; recommending Easy Tea hybrid tea cultivars; selecting Louisiana Super Plant roses; initiating a Gulf District Rose of the Year program; par­ticipating in the American Garden Rose Selections and American Rose Trials for Sustainability studies and more.

Louisiana is home to both of the relatively new national programs to evaluate roses. The American Garden Rose Selections (AGRS) debuted in 2013, and the American Rose Trials for Sustainability (ARTS) began plant trials in 2014. The LSU AgCenter is participat­ing in both of these programs.

AGRS is replacing the All-America Rose Selections program. The last winner in this program was named in 2014, and the first winners in the new AGRS pro­gram will be in 2016. This trial embodies a model using a long-used rose trialing method from Germany. This method includes evaluating disease resistance, hardiness, attractiveness and habit for both sustainability and marketing. Roses are not treated with any pesticides in the evaluations. United States region­al winners will include the Northeast, Southeast, North Central, South Central, Northwest and Southwest. The LSU AgCenter Botanic Gardens at Burden is one of 12 AGRS trial sites in the country. The motto of this new program is “bring­ing you great roses you can grow where you live.” The initial winning varieties for 2016 are Looks-A-Likes Phloxy Baby, Thomas Affleck and Dee-Lish. You can see more information on ARGS trials at www.americangardenroseselections.com.

The first year of the American Rose Trials for Sustainability evaluations in Louisiana was 2015. The goal is to iden­tify, through regional evaluation and testing under low-input conditions, the most disease- and pest-resistant, hardiest and best garden-worthy rose cultivars. In addition, the trials provide the indus­try and gardening public with objective, accurate and reliable information about the cultivars tested for each region. The methodology used will establish and maintain an environmentally responsible testing model that incorporates current research-proven landscape management techniques for the evaluation of rose cultivars for regional suitability in the United States for landscape use under minimal input conditions. More infor­mation on ARTS trials is located at www.americanrosetrialsforsustainability.org.

Kordes Rose Trials

The LSU AgCenter is also looking for the better-performing Kordes rose varieties for the Gulf South. Kordes is one of the largest and one of the oldest rose-breeding companies in the world. Fungicides are not used in their rose development and evaluations. Disease resistance in hybrid teas, sustainabili­ty in rose growing and growing “own- root” modern roses can be achieved with some of these varieties. Well-known older Kordes varieties that have successfully been growing in Louisiana many years include Shreveport and Iceberg.

Some of the newest Kordes hybrid tea and floribunda roses being evaluat­ed at the Hammond Research Station and at the Botanic Gardens at Burden include Beverly, Grand Amore, Pink Enchantment, Sunny Sky, Wedding Bells, Winter Sun, Poseidon and Summer Sun.

More Rose Trials – David Austins, Easy Elegance, Easy Teas

David Austin English roses are crosses between modern and old garden variet­ies. They have the profuse flowering of modern roses along with the fragrance and disease resistance of older garden roses. A new three-year AgCenter trial on these varieties started in 2014 and includes observations of factors such as flowering, plant size, flowering cycles, leaf spot susceptibility, blackspot suscep­tibility and more to determine the best of these roses for south Louisiana. The study is partially financially supported by the Louisiana Society for Horticultural Research. Plants are being exposed to typical rose cultural practices with the exception of disease and pest control; fungicides and insecticides will not be used.

The five most popular David Austin English roses in Louisiana are Graham Thomas, Heritage, Pat Austin, Abraham Darby and Molineaux. Prior studies in Louisiana from about 10 years ago found Heritage and Molineaux to be the best performers, with other top perform­ers being Abraham Darby, Tess of the d’Urbervilles, Benjamin Britten, Jude the Obscure, Charlotte and Cordevale.

Easy Elegance roses from Bailey Nurseries have been trialed in Louisiana to a small degree before, but a 2015 plant­ing at the gardens in Shreveport along with AgCenter gardens in Hammond will help to clarify the best of these roses for the Gulf South. Easy Elegance roses – such as My Girl – have been proven to do very well in other trials in the South and in previous trials in Louisiana.

Any Louisiana rose research article must mention the Easy Tea Hybrid Tea Rose trial winners from the four-year AgCenter study at the Gardens of the American Rose Center. Tahitian Sunset, The McCartney Rose, Fredric Mistral, Traviata and Pink Traviata were treated with fungicide only four times annual­ly in a minimum-spray study and were shown to be blackspot free for the majori­ty of the four growing years.

Gulf District Rose of the Year

The American Rose Society Gulf District, which includes Louisiana and Mississippi, started a rose-of-the-year program in 2015. AgCenter research observations are included in the selec­tion process. The inaugural winner was Belinda’s Dream.

Belinda’s Dream has proven to be one of the best in Louisiana. It is frequently recommended by rosarians in the South as the “rose to grow” for rose-grow­ing first timers. Belinda’s Dream has an attractive shrubby growth habit and excellent disease resistance. Bushes reach heights of 5-6 feet with an equal spread, but they can be easily maintained at 4 feet. Flowers are medium-pink and fully double with the form of hybrid tea roses. The fragrant blooms are larger than most landscape roses and produce spring through fall. Belinda’s Dream is an excel­lent low-maintenance, easy-care land­scape rose with large hybrid-tea flowers.

The 2016 Gulf District Rose of the Year is Cinco de Mayo. This floribun­da rose has done well in southern U.S. trials since its 2009 introduction from Weeks Roses and is an All-America Rose Selections winner. Cinco de Mayo flow­ers have 25 petals, are 3 to 3 1/2 inches in diameter and are slightly fragrant with the scent of cut apples. The uniqueness of Cinco de May is the bloom color – described as smoky lavender to a blend of rusty-orangy red. In the landscape, Cinco de Mayo is a slower grower. Mature height is 36-42 inches with an equal spread. Plants have a nice deep glossy green foliage appearance

Roses have a great tradition in Louisiana, and AgCenter horticultur­ists hope this will continue. Research is finding new roses for improved landscape performance.

LSU AgCenter Louisiana Super Plant roses include Belinda’s Dream, Red Drift, Pink Drift, Peach Drift, Apricot Drift, Popcorn Drift, Icy Drift, Sweet Drift and Coral Drift.

Allen Owings is a professor of horticulture at the LSU AgCenter Hammond Research Station and Gulf District director for the American Rose Society.

Portions of this article were previously published in a publication of the American Rose Society, the American Rose Annual 2015 edition. Used with permission.
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The Rose Garden and the Steele Burden Memorial Orangerie at the LSU AgCenter Botanic Gardens at Burden in Baton Rouge. Photo by John Wozniak

Cercospora-leaf spot .jpg thumbnail

Cercospora leaf spot is higher in occurrence in Louisiana and the Gulf States when compared to other areas of the country. Photo by Allen Owings

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Belinda’s Dream in the Earth Kind Rose Trials at the LSU AgCenter. Photo by Mark Claesgens

Cinco de MayoRose.jpg thumbnail

Cinco de Mayo, the American Rose Society Gulf District (Louisiana and Mississippi) Rose of the Year for 2016. Photo by Allen Owings

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