magnolia suddenly sick

I have a virginia magnolia about 5 yrs old. It has thrived every year as is this year. Only four days ago I noticed that the leaves are dying rapidly. There appears to be no insects or tree damage . Just the leaves are dying. it hasnt bloomed yet but the buds are present. can anyone help? Thanks

 

Take samples to Cooperative Extension or Master Gardener clinic.

 

Being a southerly species, its leaves might not have liked the past winter. Do follow Ron B's suggestions.