knock out roses and virus

Asked March 23, 2016, 6:42 PM EDT

We live in a large landscaped community in Northern Virginia. Last year our long term landscape contractor recommended we remove a section of knock out roses which were showing signs of disease. We did and replanted that area with other materials. Now, the same firm is recommending knock out roses for another area of the same property with the assurance that there are now knockout roses available which are not susceptible to this virus.

Your observation/comments requested.
to clarify; At the link below is the disease we are talking about: And my question is: where is the industry breeding/commercial distribution on this specific problem? http://thedailysouth.southernliving.com/2013/04/21/is-knockout-rose-down-for-the-count/

Alexandria Virginia disease issues roses knockout roses horticulture

2 Responses

As far as I have been able to determine, there is no evidence supporting the claim that there are Knockout roses that are resistant to rose rosette disease. I am researching the matter further with some rose experts and will reply again as soon as I have heard from them. Work is being done, primarily to find cultivars that are not appealing to the mite that spreads the disease, but also to determine if some crosses can be made to breed in the resistance to the disease itself.

I sincerely hope the landscape company you are dealing with knows what they're talking about because this has become a major issue for anyone who loves roses. If you can get the names of the cultivars they are recommending it would help in my research. If you get additional information on them, please use the reply feature within this email so it will come directly to me instead of being sent out to the general group for an answer.

Sandra Gentry

I have heard from several rose experts regarding rose rosette disease and they all agree that there are NO roses that are resistant to this pest. The suggestions given were for someone familiar with the problem to walk the property several times a year and note any roses that show signs of the disease and have them removed. The proper way to remove them is to bag them in place with plastic bags prior to cutting or digging so the mites don't disperse to other plants in the area, then dispose of them in the trash. Do not compost them.

Alternatively, a careful spray program for the specific mites that transmit the disease may keep new plantings from becoming infected. The program must be done properly and regularly especially in an area where the disease has been present in the past. If whoever maintains the landscape is qualified and conscientious, it's possible to have a nice planting of roses that may last for years. But it will be a high maintenance project.

This publication from Virginia Tech gives a lot of information on rose rosette disease and the issues surrounding the problem.

Unfortunately, this is a very widespread problem but many folks are working on a solution. The people in the industry would be jumping for joy to find resistant roses but it hasn't happened yet.

I will keep this email chain and if I hear any hopeful news, I will contact you again. I'm sorry to be the bearer of bad news, but better to know the truth than for the community to spend money on plantings that may need to be removed again in a few years.