If you have been following me on social media you’ve seen how my roses have been plagued by the dreaded rose rosette disease, which is caused by the rose rosette virus. I first saw these on one of the roses in my knockout rose hedge.
Later that year a white drift rose, that used to be in the place of the pink yarrow in the below picture fell prey to this virus.
This year another knockout rose from the above hedge was infected, which was soon followed by the middle one in this drift rose border below. We ended up removing all of the below roses for fear that it might spread to the ones nearby.
Lately, I have also noticed that a lot of the knockouts in our community are infected. Sadly most of the landscapers that work here are either unaware or don’t care about this, which results in the disease spreading, infecting all the other roses in the area. As always the first step to curb the spread is to educate everyone about the disease, how to spot, and how to treat it. Hence this post and video tutorial.
The disease is spread by a very tiny mite called the eriophyid mite, which travels from one plant to another. The mite is so tiny that it is often carried by the wind, putting any nearby rose bushes at risk. Usually the host plant for the virus is a multiflora rose, which is an invasive rose, that is very common in our woodlands here in VA.
How can you spot the rose rosette disease?
- Dark red new growth, which is oddly formed and does not turn green over time
- Cluster of small deformed branches and flower buds coming out of a new growth or Witches Broom (a tell tale sign)
- Thick stems with excessive thorns
- Deformed or elongated leaves
- Stunted or deformed flowers
An infected plant may exhibit one or more symptoms of the disease. The common ones I have seen are the dark red new growth which refuses to turn green with time, witches broom, and excessive thorns. People always get confused by the red growth as it is very normal for new growth on a rose to look red. In the below photo, the buds you see on the left are a good example of good new growth while the red buds on the right are a sign that this plant is infected with the rose rosette disease.
What is the treatment for an RRV infected rose?
Unfortunately there really is no treatment. You have to remove the entire plant before the mites on the infected plant spread to another one close by. Pruning just the infected stems is not recommended as the virus might have already spread to other parts of the plant, even though there are no visible signs elsewhere on the plant.
Are there any preventive measures you can take?
Yes, there are a few that will reduce the chance of a rose getting infected with this disease.
- When planting a rose hedge make sure that the bushes are not very close to each other. This will deter the mite from travelling from one plant to the next.
- Prune the roses in late winter or spring aggressively. This will ensure that any mite eggs that overwinter in the bushes are eliminated
- As soon as you spot the disease remove the whole plant
- Clean the tools you use to prune or dig the plant out with a diluted bleach solution (this is more of a safety measure as latest research indicate that the mites don’t spread via tools used on an infected bush)
- Do not plant a rose in the same spot as an infected rose for the next 3-4 years. Latest research has shown that the virus does not survive in the soil however most often some roots of the infected plant are left behind. Because of this there is a high chance that the virus in those roots will infect a nearby rose plant.
As you can see in the video this problem is very prevalent here in zone 6b in VA and unfortunately I don’t see it going away anytime soon. Between the Japanese Beetles, humidity related issues like the black spot, rose sawfly, and now this rose rosette virus, it is becoming extremely hard for us to grow roses here. What a shame as these gorgeous beauties deserve a prominent place in every garden! Do you have the rose rosette disease in your neck of the woods?