Clyde, Sorry for the delay in responding. I grow several carexes here in Georgia. I checked the published hardiness on many that I grow and here are 3 that are hardy to Zone 5. I have all of these available.
C. conica 'Marginata' zone 5-9
C. morrowii 'Variegata' zone 5-9
C. plantaginea Zone 4-9
Regards, Richard Jolly
Pine Forest Gardens Grower of Quality Hostas
On Line Catalog