I have what I believe is a snowbird hawthorn (about 10 years old) in our backyard and last summer the leaves were getting rusted spots on one side with fungus looking spots on the undersides. They slowly spread throughout the tree and the tree lost its leaves quite early. The tree was slow to bloom but came back no problem in the spring, but I am now noticing that the spots are coming back. It seems like Cedar Hawthorn Rust but is there anything I can do to help the tree get rid of it or does it need time (I’ve read 24 months) to complete it’s cycle?
Hello @leahdzimmer. You have a case of juniper-hawthorn rust on your tree. It’s very similar to cedar apple rust; the difference being the trees affected. Are there juniper trees/low-lying shrubs in the vicinity? If you have them in your yard, look for orange glutinous blobs in the juniper in late summer. If you spot them, cut them off and destroy them so the spores cannot become airborne to affect your tree. Remove as many of the worst affected leaves on your hawthorn as feasible without completely defoliating your tree. The remaining leaves can be sprinkled with sulphur dust. Here’s an article that will provide further insight:http://www.salisburygreenhouse.com/orange-fungus-on-evergreens/
Some people will go as far as removing either the juniper or the hawthorn to interrupt the cycle. This is what I consider to be a last resort though.