Rose rosette disease is a harmful, rapidly spreading rose virus that can pose a threat to the beauty of our rose gardens.
Staying informed on the topic is our key line of defense against this rose disease.
In this article, we’ll be taking a detailed look at rose rosette disease and answering all the questions you may have about it.
- What Causes Rose Rosette Disease?
- Rose Rosette Disease Symptoms
- How To Identify Rose Rosette Disease
- Rose Rosette Disease Treatment
- How Long Does Rosette Stay In The Soil?
- What To Plant After Rose Rosette Disease
- Rose Rosette Disease Vs New Growth
- Rose Rosette Disease Prevention
- Roses Resistant To Rosette Disease
- Conclusion
- FAQs
What Causes Rose Rosette Disease?
Since its discovery in the 1940s, scientists are still uncertain of what causes rosette disease, but they believe that it could be caused by the rosette virus from the Emaravirus genus.
However, they do know that this devastating disease can be spread from plant to plant via an eriophyid mite known as Phyllocoptes fructiphilus.
This pest is small enough to be carried through the wind.
Once it has landed on a plant, it proceeds to take residence in the axils on the base of the rose leaf.
These mites have a preference for smaller spaces, making shrubby roses a target for this pest.
Rose Rosette Disease Symptoms
The list of symptoms for rose rosette disease can be lengthy and vary between different cultivars of rose.
Here are some of the most common symptoms associated with rose rosette disease:
- Distorted and discolored leaves: Leaves affected by rose rosette can have a mottled look with reddening of the veins. The shape of the leaves can start to deform as well.
- Excessive thorn production: In this situation, the branches of your rose plant have become overrun with soft, rubbery thorns, covering the stems entirely.
- Witches’ Broom Branches: The canes of the plant begin to sprout stubby clusters of stems with thick leaflets. This symptom is called witches’ broom due to its appearance.
- Deformed and discolored flowers: Roses forming on an infected plant can appear to be stunted and abnormally colored. Multiple flowers forming in a single bud is also not uncommon.
How To Identify Rose Rosette Disease
If any of the symptoms discussed previously seem to be happening to your rose plant, then this can very likely be a case of rose rosette disease.
The most telltale symptoms of RRD are excessive thorn production, reddening of leaves, and witches’ broom branches.
These symptoms can appear as early as three weeks, or in some cases, there is an incubation period of at least one year.
Rose Rosette Disease Treatment
If you are all but certain that your rose is a victim of RRD, then there are two options you can take to confirm and stop the spread.
- Option 1: If you are lucky enough to catch the disease in an early stage, then it is imperative to remove the infected cane as soon as possible. Cut off the infected area and quarantine the severed branch in a plastic bag.
- Option 2: If the disease is in an advanced stage you should send a sample to a nursery or a local extension office for rose rosette disease can be confirmed with laboratory testing. When rosette disease is confirmed, there is nothing more gardeners can do to stop it other than remove the plant entirely.
Place a plastic garbage bag over the entire plant before digging up the root ball.
Please do not try to cut down the plant without covering it securely in plastic. This will help reduce the chance of passing mites onto other nearby rose plants.
Seal the bag and place it in the trash in order to prevent the spread of disease.
Continue to monitor the other roses in the area for any signs of disease. Act accordingly if the rosette disease persists.
How Long Does Rosette Stay In The Soil?
Luckily for gardeners, rose rosette disease itself cannot survive in the soil for very long. However, this disease could still live within the roots of the plants.
If the root system of the plants is not removed in its entirety then there is a strong possibility that RRD could still stay in the soil for at least 2 to 3 growing seasons.
What To Plant After Rose Rosette Disease
Rose rosette disease only affects members of the Rosa genus.
Therefore, you can replace the removed roses with any other type of plant, as long as they are not a Rosa species.
However, we understand it can be hard to replace your beloved roses with an entirely different plant.
Unfortunately, the safest option is to wait 2 to 3 growing cycles for the disease to completely pass over.
In the meantime, we suggest planting annuals in place of your roses.
Annual plants only live for about one growing season, making them less of a commitment than a perennial plant.
Your garden will still be able to have lush flowers every summer. Before you know it, those 2 growing seasons will pass by and you can safely re-plant your rose bushes.
Rose Rosette Disease Vs New Growth
Differentiating between rose rosette disease and normal new growth on rose bushes is important to avoid misdiagnosis.
Some varieties of roses have normal growth patterns that may be very similar to some of the symptoms of rose rosette disease.
Let’s take a look at some common examples so we know what to look for:
- Rosette disease can cause a characteristic “witches’ broom” growth pattern. In this situation, many thin, elongated stems emerge from a single point on the affected rose bush. This growth is different from the normal new growth of a healthy rose plant. Usually consists of a single stem emerging from a bud.
- Some cultivars of rose have a normal reddish hue when new growth comes in, but this hue will eventually turn to a uniform green as the plant matures. This differentiates from RRD, which causes roses to turn a reddish color and become deformed in shape.
Rose Rosette Disease Prevention
Rose rosette disease has no treatment. When a plant is affected by RRD, it is certain death.
The next best option to defend your plants against this disease is by preventing it from ever happening.
Here are some tips for preventing RRD:
- Remove host plants: Multiflora roses (wild roses) are most likely to carry the mite that causes rosette disease. If you have wild roses in your area, then work with your local community to remove wild roses from the area.
- Deadhead roses: Mites overwinter in flower buds and seed heads. Prune these flowers as soon as the blooms begin to wither and dispose of them in the garbage.
- Keep your roses healthy: a stressed or unwell plant is most likely to fall prey to disease of any kind. Promote healthy rose growth by keeping your roses hydrated, fertilized, and given plenty of sunlight.
Roses Resistant To Rosette Disease
While no rose is completely resistant to rose rosette disease, some roses are less likely to harbor the Phyllocoptes fructiphilus mite that carries RRD.
As we’ve discussed previously, this mite prefers to house itself in the small crevices at the base of the rose leaf. As a result, smaller, shrubbier roses tend to make the best homes for this mite.
On the other hand, the joints on hybrid tea roses tend to be more open, leaving fewer crevices for the Phyllocoptes fructiphilus mite to hide in.
This makes hybrid tea roses less likely to house the disease carrier.
Although it is less likely, gardeners should still be alert as this is not 100% foolproof.
Conclusion
Rose rosette disease remains an adversary to gardeners everywhere.
While this disease may be stealthy and fast-acting, we can stay one step ahead of its spread.
With early detection and intervention, you can quickly stifle a rosette disease pandemic from happening in your garden.
By staying informed about rose rosette disease, you can enjoy healthy, bountiful blossoms for many years to come.
FAQs
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