I have 2 evergreen magnolias that were planted last summer that so far this spring look awful. the once beautiful dark green leaves are a pale yellow/green and many are dying or rusty looking. I fertilized about a week ago but haven't seen any change so far. My yard is very heavy clay but I did dig out quite a huge hole and replaced the soil with topsoil/compost and bone meal. Is there hope that these will bounce back and green up once the rain subsides? What else can I do?