How do I get rid of rust on a hawthorn tree and what fertilizer should I use to feed the tree?
Our home is on the Eastern Shore of Maryland.
Certified GKH Gardening Expert
This is unfortunate, since this will be incurable. You can treat the disease, but eventually it will kill the tree.
This article will help: https://www.gardeningknowhow.com/plant-problems/disease/cedar-hawthorn-rust-disease.htm
As far as what to feed them... Any well balanced fertilizer will be fine once per year. This article will help: https://www.gardeningknowhow.com/ornamental/trees/hawthorn/growing-hawthorn-trees.htm