By Stan V. Griep
American Rose Society Consulting Master Rosarian – Rocky Mountain District
Rose mosaic virus can wreak havoc on the leaves of a rose bush. This mysterious disease typically attacks grafted roses but, in rare cases, can affect ungrafted roses. Keep reading to learn more about rose mosaic disease.
Identifying Rose Mosaic Virus
Rose mosaic, also known as prunus necrotic ringspot virus or apple mosaic virus, is a virus and not a fungal attack. It shows itself as mosaic patterns or jagged edged markings upon the leaves of yellow and green. The mosaic pattern will be most obvious in spring and may fade in the summer.
It may also affect the rose flowers, creating distorted or stunted blooms, but often does not affect the flowers.
Treating Rose Mosaic Disease
Some rose gardeners will dig out the bush and its soil, burning the bush and discarding the soil. Others will simply ignore the virus if it has no effect upon the bloom production of the rose bush.
I have not had this virus show up in my rose beds to this point. However, if I did, I would recommend destroying the infected rose bush rather than take a chance upon it spreading throughout the rose beds. My reasoning is that there is some discussion about the virus being spread through the pollen, thus having infected rose bushes in my rose beds increases the risk of further infection to an unacceptable level.
While it is thought that rose mosaic may spread by pollen, we know for a fact that it does spread through grafting. Oftentimes, rootstock rose bushes will not show signs of being infected but will still carry the virus. The new scion stock will then be infected.
Unfortunately, if your plants have the rose mosaic virus, you should destroy and discard the rose plant. Rose mosaic is, by its nature, a virus that is just too tough to conquer currently.