Like most macs, it should be root hardy in zone 5 but will require winter protection to produce flowers. If received as an Easter gift already in bloom, you will need to keep it indoors until after your last frost date, then gradually acclimate it to the outside. And greenhouse or florist hydrangeas (those sold in bloom out of season as gifts) often do not transition well to the outdoors in colder zones.

Additional info should be available under the registered name, Hydrangea macrophylla 'Leuchtfeuer'.