What is Rose Rosette Disease? (Cause and Solution?)
As you might have guessed, rose rosette disease is a plant malady that’s particular to only roses. But not many home gardeners are aware of why this happens and how to deal with it. Today, I’ll tell you all you need to know about it!
Rose rosette disease is a condition affecting rose bushes that have been infected with Emaravirus sp. carried by a tiny eriophyid mite. This has no cure and all affected plant parts, including roots must be discarded completely to prevent further spread in the garden. One way to prevent severe cases of rose rosette disease is to separate rose bushes.
I have heard countless stories of people attempting to save their precious rose bushes from rose rosette disease even if it has started wreaking havoc by pruning infected parts. Will you be able to treat it effectively like this? Scroll on to find out!
Rose Rosette Disease: Why Does It Happen in Rose Gardens?
Although rose rosette disease is spread in gardens by eriophyid mites, it is more specifically caused by an Emaravirus. It was first documented in Rocky Mountain wild roses during the 1940s. Multiflora roses are especially prone to getting this disease.
Good news! Among the thousands of varieties and hundreds of species of roses that you can fill your garden with, the main host of rose rosette disease is the multiflora rose (Rosa multiflora).
Such roses are wild and viewed as noxious weeds throughout pretty much the whole US territory.
In other words, garden roses are less likely to catch it than landscape wild roses. But again, it’s not totally impossible to rose cultivars and varieties in home gardens to contract the rose rosette disease.
Learn the difference between these in our article on why roses have “thorns”!
Wingless eriophyid mites (Phyllocoptes fructiphilus) are likely to stay by the top of rose bushes. They commonly feed and reproduce around the area because that’s where there is tender growth of buds and shoots.
They then infect the rose plant with the virus while feeding on it. As they spread, so will the virus. You might unwittingly spread the virus in your garden too!
Eriophyid mites carrying the virus that causes rose rosette disease is less than 0.005 in (0.13 mm) long so they are easily carried by the wind. They can also be transferred by gardening gloves and tools.
So, as always, I strongly recommend you disinfect your tools as often as possible—before and after you use them. As the saying goes, it’s better safe than sorry.
A small rose bush can be wiped out and killed by the rose rosette disease in more or less 2 weeks. Meanwhile, a larger and more mature rose bush can experience significant damage in about 5 years.
What are the Symptoms of Rose Rosette Disease?
The signs and symptoms of rose rosette disease are
- Rapid elongation of shoots
- Red discoloration of infected parts
- Excessive prickles or “thorns”
- Distorted small leaves
- Thickened canes
- Proliferation of shoots or branches (witches’ broom)
- Misshapen buds and flowers
- Discolored flowers
- Spiral growth of canes
- Defoliation or lack of leaves
- Abnormal rapid leave growth
- Brittle yellowing mottled leaves
- Overabundance of leaves
- Shortened internode
- Branch dieback
- Reduced tolerance to cold temperatures
- Increased risk of fungal diseases
Mites carrying rose rosette disease can overwinter and cause damage to your lively bushes starting in spring.
But keep in mind that these symptoms may vary depending on the rose you have growing in your yard.
Also, it’s important to note that some of these signs may look similar to damage from other causes such as herbicides including glyphosate and 2,4-D.
Transmission of the Emaravirus that causes rose rosette disease often happens from May to July.
Regularly monitor your roses for these signs early on so that they can be diagnosed and treated as early as possible!
Getting Rose Rosette Disease Properly Diagnosed!
One of the main issues with rose rosette disease is that it can be hard to correctly diagnose unless the damage is already severe.
This is especially true for regular home gardeners since we don’t have high-powered microscopes to spot eriophyid mites. Don’t sweat it, though. Experts in your local Extension office can help!
To get your rose bush properly diagnosed with rose rosette disease:
- Carefully cut off 6–12-inch (15–30 cm) shoots, preferably with open buds, from your bush that are showing signs of the disease.
- Secure all shoots in at least one layer of dry newspapers or paper towels.
- Place the wrapped-up shoot samples in a resealable plastic bag or container.
- Store the packed shoot samples in the fridge until it’s time for delivery.
- Take the secure shoots to the Extension office in the county.
It’s best to take as many close-up pictures as you can of the bushes you suspect are infected with rose rosette disease.
How Do You Properly Treat Rose Rosette Disease?
The only way to treat rose rosette disease is to destroy infected bushes immediately. All parts of infected rose plants must be thrown away in sealed plastic bags or burned. Otherwise, it can easily spread and affect all other roses within proximity.
If you hear someone say that you can salvage an infected rose bush, don’t believe them. You see, the truth of the matter is you can’t fix rose rosette disease!
Other than that, you can only manage and control it. But you can’t bring it back to its former glory no matter how hard you try. Even experts will agree with me here.
So although it’s painful, you have to start pruning off all infected shoots. Then you need to completely remove every single trace of that rose bush from your garden—root ball included. Then throw them all into a plastic bag, seal them, and throw them in the bin!
After that, make sure to disinfect all the tools and clothes you used while removing the infected roses. Mites might’ve hitched a ride on those.
Before replanting, it’s best to go for a 2-month fallow period in the area where your rose bush grew. If any rose sprouts pop up, remove them too.
In the meantime, consider growing other equally stunning flowering plants in your garden that won’t be affected by rose rosette disease. Such plants include abelia, butterfly bush, dwarf crape myrtles, and hydrangeas.
Check out more in our article on flowers perfect for dates!
With non-rose plants, you can replant the area immediately!
How Do You Prevent Rose Rosette Disease? (13 Tricks!)
Prevent rose bushes from getting infected with rose rosette disease by
- Closely inspect all new rose plants before buying and planting them
- Provide sufficient space in between rose bushes (at least 2ft)
- Interplanting non-rose ornamental plants with rose bushes
- Position tall barrier plants on the windier side of the garden or yard
- Monitor all roses for signs of rose rosette disease throughout the season
- Deadhead spent roses throughout their blooming period
- Get rid of any wild rose species, like multiflora, that appear in the garden
- Regularly prune rose bushes during winter
- Spray dormant oil on rose bushes after winter pruning
- Apply insecticidal soaps or horticultural oils in winter and summer to kill mites
- Do not use leaf blowers near rose bushes
- Ensure proper irrigation for rose bushes, especially during drought
- Have the soil analyzed regularly to make sure that it is fertile
Can you save a rose with rose rosette disease?
Rose bushes that are already infected with rose rosette disease can no longer be saved as there is still no known cure for the condition. Even though some have reported successfully preventing severe infection with pruning, it is often ineffective at permanently treating rose rosette disease as the virus can rapidly spread throughout the plant.
Are there any roses that don’t get rose rosette disease?
Most cultivars and varieties of roses are believed to be susceptible to the rose rosette virus. However, some rose species are even more resilient to the disease such as R. aricularis, R. arkansana, R. blanda, R. carolina, R. palustris, R. setigera, and R. spinosissima.
Summary of What is Rose Rosette Disease
Rose rosette disease is spread by wingless eriophyid mites carrying Emaravirus. Multiflora and landscape roses are said to be particularly prone to catching this disease. However, even garden cultivars and varieties of roses can be affected by the rose rosette virus.
Bushes and plants with rose rosette disease may display a wide variety of symptoms including red growth, witches brooms, excessively prickly canes, and distorted flower buds.
Gardeners need to discard and destroy rose plants infected with rose rosette disease entirely. Otherwise, it can spread and affect other rose species due to how easily mites, along with the virus, can spread. Nevertheless, precautionary measures can prevent it.
- “Rose Rosette Disease” by Jennifer Olson, Eric Rebek, and Mike Schnelle in the Oklahoma State University
- “Rose Rosette” by n/a in the Missouri Botanical Garden
- “Frequently Asked Questions About Rose Rosette Virus” by Millie Davenport in the Clemson University Cooperative Extension