Rose Rosette Disease Update
Based on feedback from our Master Gardeners at last week’s Payne County Fair, Rose Rosette disease is the most common pest problem facing gardeners in our area. We’ve talked about Rose Rosette several times in this column, but in case you missed it, here’s a brief review. There are several key signs but it is important to remember that each of these must be considered as a part of a complete diagnosis as some of the individual symptoms can be caused by other factors, none of which are as problematic as this disease.
- Thorn proliferation. Some cultivars of roses naturally produce more thorns than others so the key here is to look for huge increases in the number of thorns on the affected area compared to other parts of the plant.
- Leaf distortion and unusual red color. To repeat the opening statement, red color in itself is normal for new growth on many cultivars.
- Unusual shoot elongation in combination with some or all of the above symptoms.
- Witches Broom. Severe leaf, stem deformation with very large numbers of thorns. At a glance, canes showing severe witches broom will appear to be a completely different plant compared to the healthy portions of the rose.
The bad news is there is not a cure once roses have been attacked by Rose Rosette. The very best a gardener can do is postpone the inevitable decline by aggressively pruning away the affected portions of the plant. Two important notes: This disease is a virus so take extreme care to sterilize your pruners before moving on to healthy parts of the plant. Also, the virus is transmitted by a microscopic mite. It is very easy to transmit this mite to other plants with your gloves, clothing, or careless disposal of trimmings. It is best to place a plastic bag over the affected stem, prune it away, and discard it.
For complete information on this disease, see OSU Fact Sheet #EPP-7329 Rose Rosette Disease (PDF/Mobile).
As far as replacement plants, gardeners know there is not really a true replacement for the rose. However, some plants that do well in Oklahoma and can effectively replace roses in some landscape situations include: abelia, autumn sage, butterfly bush, crapemyrtle, deutzia, hydrangea, spirea, St. Johns wort, summersweet, and weigela.
At first glance, you may disagree with this list. Before disregarding these possible replacements completely, look carefully at some of the newer cultivars as breeders have done a lot of work over the last several years introducing dwarf selections to some of these trusted landscape standards.
For more information on this or any other horticultural topic, you can contact Keith Reed, the Horticulturist in the Payne County Extension office. Keith can be reached via email at firstname.lastname@example.org, phone at 405-747-8320, or in person at the Payne County Extension office, located at 315 W. 6th in Stillwater.
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