you could manage a good rose garden even with rose rosette disease in your area.
This guide explains what rose rosette disease is and where it’s a problem.
You’ll also learn what the major symptoms are so you candiagnose and manage RRD in your garden.
Credit: Denny Schrock
Plus you’ll gettips for preventing RRD from infecting your rosesin the first place.
What is rose rosette disease?
RRD is a so-far-incurable illness resulting from a virusthat only affects roses.
Afflicted plants quickly lose their garden value.
The severity of the virus and its ability to quickly spread have changed the way gardeners should approachgrowing roses.
By the early 2000s, it had become the most significant disease of garden and landscape roses.
Where is rose rosette disease a problem?
RRD is established in parts of the United States and Canada.
Sightings have also been reported in India, China, and more recently the Netherlands.
Experts have different opinions about the likelihood of further spread.
Theres a lot of areas where you dont see much of it, says Byrne.
There seems to be a northern limit for one.
And going south, there seems to be a line at Northern Florida.
Sustainable Roses maintains aconstantly updated map of RRD sightingsacross the US.
you might alsoreport your own sightings and post pictures for an expert diagnosis.
Check your roses a couple times a week during the growing season to catch symptoms as early as possible.
Major symptoms
Often multiple symptoms appear together.
The more you see at once, the more scrub the diagnosis.
Unfortunately, a rose can also carry the virus for years without showing symptoms.
Most roses produce soft, reddish new growth with smaller leaves.
Some roses, like Chinas, produce multiple stems from a single node.
Dont confuse them with witches brooms.
There are also harmless rose oddities.
For example, you might see proliferation, which is a flower emerging from the middle of another flower.
Stem fasciation, which is when stems grow flat like a ribbon, is another oddity you might see.
Extreme versions of this are sometimes referred to as devils tongues.
Despite the diabolical nickname, its actually harmless by itself, and can just be cut off the plant.
However, the abnormal leaves will often look chlorotic or whitish when herbicides are to blame.
And herbicide damage doesnt cause witches brooms, hyperthorniness, or redness.
Additionally, there are other rose diseases like rose mosaic virus that arent an emergency.
The vector, which spreads the disease, is awingless, microscopic mitenamedPhyllocoptes fructiphilus.
It only lives and feeds on roses.
After the virus goes through the mites gut, it makes its way into its saliva.
If the mite blows onto an uninfected rose, it will suck sap from it too.
Some of its infected saliva will enter the new rose and potentially infect it with RRD.
The mites can also move from one rose to another if the two plants are touching.
it’s possible for you to also get genetic testing done at a plant diagnostic clinic.
But the longer you wait, the more likely the rose will infect another rose.
According to Byrne, if you are positive your rose has RRD, “you should remove it.”
Andremove the infected plant carefullyto avoid spreading mites.
Prune it back close to the ground stem by stem.
Place the stems in a garbage bag or box as you remove them.
Then dig up what’s left.
Get as much of the roots as it’s possible for you to.
They congregate on witches brooms in 40 to 50 times the numbers they do on regular growth.
Then, dig up the rest of the rose plant as soon as you’re free to.
Then start with clean roses, stay clean, and dont spread it," says Al Rwahnih.
“Look at the plant youre buying and double-check its free of symptoms.
Ask the nursery whats the source of their plant material.
During the season you might alternate between two types of miticide once every 2 to 3 weeks.
Ron Ochoa, a USDA entomologist researching the mites, says they only live 10 to 15 days.
Timing your applications to the mites life cycle is a key to successful miticide tool.
Future Hope for Roses
One day, RRD may become rarer and less destructive.
Byrne estimates that his breeding program may get RRD-resistant roses on the market in as few as 10 years.
Other hybridizers are using his research to produce their own resistant varieties.
Frequently Asked Questions
Currently, a rose infected with rose rosette disease cannot be saved.
You should immediately remove any infected rose so that it doesnt spread the disease to other roses.
By removing any infected plants from your garden and looking for infected plants nearby.
Yes, but youll want to take a few precautions.
Remove any infected roses completely, roots and all.
Sometimes small pieces of vigorous rootstocks or suckering roses survive and re-emerge when you thought youd removed them.
Also verify you get RRD under control if you have other roses before you replant.
Lau J, Young EL, Collins S, et al.
Rose rosette disease resistance loci detected in two interconnected tetraploid garden rose populations.
July 6, 2022.
Accessed August 5, 2024. https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.916231/full.
2023; 12(4):575.
2022; 11(6):660.
