hey all, I was wondering if you could help me identify what is wrong with my dogwood (Cornus Florida). The tree is located on a southern exposure in the Okanagan so I am assuming it is most likely heat exhaustion but I am not 100% sure. The tree receives regular water. I have attached a few photos to show the symptoms. Any help is appreciated, Antonin
Check for dogwood anthracnose (Discula destructiva). Unfortunately, Cornus florida is very susceptible to it.
Tests of soil and water may be in order to see if nutrients, salt or sodium are present in excess. Flowering Dogwood is salt-sensitive and often has difficulty where the water is high in dissolved solids. In California's Central Valley, for example, it does well in Sacramento (where few dissolved solids are present in the water) but dies or is stunted in nearby towns which rely on marginal-quality well water. -Tony
I think you have made a good call, Tony. The leaf damage looks like too much phosphorus. However, my advice would be to take some leaves into a lab and get a tissue analysis . As you note, irrigation water can itself cause such problems so maybe a test of the irrigation water should come first. See: http://www.ag.ohio-state.edu/~bygl/images/enlt/enlt-128.jpeg for picture of anthracnose commo on BC dogwoods. If you are planting a new dogwood, look for Eddi's White Wonder as it is reputed to be resistant to anthracnose blight. imo
