by Lydia Holley March 13, 2023
Researchers have been studying Rose Rosette Disease (RRD), a virus which causes abnormal growth and the death of roses. Transmitted by mites which are carried on the wind, RRD has decimated roses in gardens throughout parts of the United States and Canada. It has made a major impact on some commercial rose gardens, home gardens, rose sellers, and rose breeders.
There are some areas in East Texas hit hard, while others have not yet seen this disease come to their gardens. If you have not run into RRD in your garden yet, be thankful. But also be wary, and check your roses for abnormal growth once or twice a year.
A new paper published on March 10 by Mark T. Windham, Thomas Evans, Sara Collins, Juniper A. Lake, Jeekin Lau, Oscar Riera-Lizarazu, and David H. Byrne studied the effect of RRD on 108 roses in a variety of climbers, miniatures, hybrid teas, floribundas, and other classifications in two different locations over three years.
Researchers are not especially looking for specific rose cultivars which show no symptoms—they are interested in knowing the parentage of roses which are resistant. This study noted that several rose species seemed to have promise of resistance, even though some of these have not been popular with breeders in the past. That may change as more results are published from various trials. Just imagine being able to buy new, beautiful roses with a resistance to this dreaded disease. It would bring hope to many who have replaced their roses with other plants due to RRD infections.
I will not list all 108 roses tested, but will try to list some in each category of high, medium, and low transmission of disease. Some of the roses in the group which exhibited few or no symptoms are: Chuckles, Fuzzy Wuzzy Red, and Sir Thomas Lipton.
Roses with moderate symptoms during the trial included: Belinda’s Dream, Bonica, Caldwell Pink, Hot Cocoa, Julia Child, Knock Out, LaMarne, Old Blush, Queen Elizabeth, and Red Drift. Interestingly, Bonica landed in the moderate list. This rose had previously been reported by a study in Arkansas to be highly resistant to the mites.
Roses showing a high incidence of symptoms included: Carefree Beauty, Coral Drift, Ducher, Nearly Wild, Sally Holmes, and Zephirine Drouhin.
If the roses named are not ones you currently grow, remember that it would be next to impossible to grow every rose in a trial. However if, like me, you are growing roses which have made the moderate or high-symptom list, do not fret. Just keep an eye on your plants and take care of any which show symptoms as soon as possible.
Right now, roses are sold with information on resistance to rust, blackspot, and mildew. In the future, you may be able to purchase roses by resistance to RRD, too. Many thanks to those studying this disease. Many gardeners are eager to learn more in future studies.
For more information, call 903-675-6130, email [email protected].
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