Hello, we have this yellow barberry in our rock garden which seems to be unhealthy. It's discoloured and having a lot of stains on it's leaves. What could be causing it? We have some red barberries as well (berberis thunbergii atropurpurea nana) and they are not doing good either. Red ones suffer from strange burn-like spots on leaves. See attached pictures. Thanks, Pavol
