Capitol Hill Garden Club In Washington, D.C., Since 1952

Rose Rosette Disease, A Modern Scourge, by Carol Edwards

September 19, 2014 1:35 PM | Anonymous member (Administrator)

Rose Rosette Disease, A Modern Scourge


As I have walked near my home recently, I have seen diseased roses in several nearby gardens. This has caused me to be afraid, very afraid!  


Rose Rosette Disease is a fatal affliction for roses. It is generally easy to recognize. New growth is deformedundefinedtwisted, perhaps with excess thorns, and often with dark reddish tips. It resembles a “witches broom”.  You can see images of Rose Rosette Disease on the Internet, http://msue.anr.msu.edu/news/rose_gardeners_should_learn_the_symptoms_of_rose_rosette_virus.  


Rose Rosette Disease is carried by microscopic mites that drift via the wind (eriophyid) from infected plants to healthy ones. Once it is well established, Rose Rosette Disease has no effective treatment. The diseased plant must be removed.  Examine your rose bushes often.  If you find the disease very early, you may be able to save the plant.  Here’s what to do:


Step 1) If you see a cane (rose branch) with deformed growth, look for others.  


Step 2)  If you find only one diseased cane, you may be able to save the plant.  Place a plastic bag over the infected cane so that the mites do not move to other branches during removal. Prune the entire cane from the bush and discard the plastic bag. Also remove fallen debris and surface soil around the base of the plant. Do not add any matter from that plant to your compost. Clean your tools with alcohol before reusing. Continue to monitor the plant closely for further signs of disease.  If deformed growth reappears, remove the entire plant immediately.


Step 3) If more than one cane on your plant is deformed, it is too late to save the plant.  The disease generally starts on one cane, travels slowly down to its base, and up adjoining canes.  If two or more canes are affected, the entire plant must go!  (Yes, boohoo, it’s really sad.)  The plant will eventually die anyway.  Meanwhile, it’s mites will spread the disease to other roses in your garden and to neighboring gardens.  All gardeners must be ruthless at times. This is one of them.


Step 4) When you remove the plant, cut up as much as possible covered with a plastic bag.  Dig out the roots. Clean the soil around the planting hole, including any fallen debris.  Do not plant a new rose in that spot immediately. Wait a season, dig out the old soil and replace it with new. Mites can over winter in the ground.


It is very important to be careful when you purchase roses.  Some roses are being infected in commercial growing yards and sold to the public.  This may be especially true for popular shrub roses sold in big box stores.  Buy your plants only from a trusted source.  Before purchase, carefully examine your selection, as well as the roses for sale surrounding it. If you see any signs of Rose Rosette Disease, walk away. If you receive a mail ordered rose during the growing season, examine it upon arrival.  If it is received dormant and small, a band or one gallon, you may want to grow it in a pot the first year, away from your established roses.


Sometimes what at first glance can appear to be Rose Rosette, is not.  If you have used Round Up near your roses, especially on a windy day, you may see some disfigured growth on your plants.  Round Up drift, as it is called, does not cause the excess thorn growth or the reddish coloring of Rose Rosette Disease. The rate of plant growth is normal.  If you have a plant with stunted tips, which you think may have been caused by Round Up drift, take a sample to a garden center information desk or Master Gardener clinic for diagnosis. 


Did I say, examine your rose plants, all of them, often? Gardeners unite. It would be ashamed to see Capitol Hill loose all of its beautiful roses. 



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