Rose Rosette Disease is Bad News for Rose-Lovers

Tell-tale witch's broom caused by rose rosette on a shrub rose

by Gene Sumi

There’s a relatively new problem suddenly appearing in our rose gardens and the news is not very good if you find that you have it.  If you’ve noticed new branches coming out on your rose bushes this spring and summer that look very different from all of the other branches on the bush, please take notice.  The branches will look very bizarre.  The leaves and sepals below the flower buds will be bright red to reddish-pink, and will be frilled and take on a feathery look.  The color of the leaves will also be very pale green, further making them stand out among the healthy branches of the bush.

This is Rose Rosette Disease (RRD), a plant virus that has infected your rose and may take it over before the season is over.  The virus has become part of the plant’s DNA, which is why the whole appearance of the rose bush has changed.  Besides the fact that this infection will cause the whole rose bush to look so different from what was there before the infection, the disease will doom the rose to a shortened life span.  Normally, a rose with RRD will die within 2 to 4 years after the infection appears.

The virus infection occurs when a species of mite called an Eriophyid mite ingests the virus from the sap of an infected rose, then travels to healthy roses and infects them when tapping into that rose’s sap system.  Eriophyid mites are extremely tiny, much smaller than common spider mites.  They are very difficult to control and the few pesticides that are effective on them are not available to the general public.

If you find your rose bush has the signs of RRD, the whole plant should be uprooted and disposed of in the trash, not in the composter.

Photo credit: Missouri  Botanical Garden PlantFinder.

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