Mountain laurel disease? - Ask Extension
Hello,
My mountain laurels are sickly and now the leaves have this pattern on them. Is this a disease I can treat them for? Thanks for your help.
Knowledgebase
Mountain laurel disease? #567600
Asked June 05, 2019, 7:18 PM EDT
Hello,
My mountain laurels are sickly and now the leaves have this pattern on them. Is this a disease I can treat them for? Thanks for your help.
County Oregon
Expert Response
Your mountain laurel is infected with a ring-spot virus.
This infection is spread throughout the plant. That is, all parts are infected.
With mountain laurel, the new leaves typically look fine but the telltale marks of the virus appear when the leaves are 2 years old. The shrub will gradually decline.
Unfortunately, the only possible "treatment" is to remove, and discard, the entire shrub.
Any search for a replacement will be a frustrating experience, this because, as was said, the new leaves look fine whereas the infection reveals itself the following year when the leaves are 2 years old.
Thank you so much Jean! I have about 40 different evergreen azaleas and rhododendrons in my yard. I did a google search and from what I could see this affects them too. :( Is that true? I am pretty concerned now since if it takes 2 years to show up on leaves all my plants could be affected which would mean pulling out the majority of my landscaping. I know there is no way to cure it but how can I keep it from spreading?
For some reason, this virus is much more common in Mountain Laurel than in evergreen azaleas or rhododendrons.
From your research, you may have already learned that the virus is spread via prorogation. In other words, via infected cuttings and/or from grafting.
I also found a site which said the virus may be spread by mechanical inoculation,a method common to some, but all, viruses. That usually refers to transfer via pruning tools. But can also refer to leaves of an infested plant rubbing against a healthy plant.
That's the most important reason why the virus-infected plant should be destroyed. You won't inadvertently spread the virus from the mountain laurel to other currently healthy plants in your garden/landscape.
Thank you so much! I just hope I haven't already transmitted it to other plants. I am removing them and will plant camellias and blueberries instead since the beds the mountain laurels are in have an acidic soil blend that was made specifically for the mountain laurels. Will this virus transmit to blueberries and camellias if I plant them in the same dirt? Thank you so much for all of your help.
Neither camellias nor blueberries are listed in our official disease management resource as being susceptible to necrotic ring spot virus.
To tell the truth, virus infections are rather uncommon in home gardens. After the virused plant is removed and destroyed, all should be well. (That's what occurred in my garden after I removed my virused mountain laurel.)
Take a few deep breaths and enjoy the next phase of your garden!
