Q. For years we have been fighting a losing battle with an anthracnose infected dogwood. We finally decided to cut and remove it this fall. However, next to the dogwood is a mountain ash that has also been infected, but not as severe. With the removal of the dogwood, will we have better success against the infected mountain ash, or will we have to remove it also? Charles Layton – Gig Harbor, WA
A. I suspect the status of your dogwood (Cornus spp.) will not influence the heath of your mountain ash (Sorbus spp.). As far as I am aware Mountain Ash are not susceptible to the various fungi grouped under the disease complex called anthracnose. You could be misinterpreting the symptoms of a bacterial disease of Mountain Ash called Fire Blight, which is unrelated to you dogwood problem. Bring a sample of the infected areas to the WSU extension for accurate identification of your Mountain Ash problem. If it is Fire Blight then pruning out diseased areas (cutting eight inches below visibly infected tissue) will go a long way to managing this problem. Be sure to clean your pruners with rubbing alcohol between cuts to prevent spreading the disease.