Although you can plant the blueberry bush in the fall in zone 5 it is safer to plant it in the spring. Wait until all danger of frost has passed and the soil dries a bit.
Test the soil pH and prepare the blueberry's soil one year before planting. According to Carol Bale, of "Chicagoland Gardening" magazine, the heavy soils in some areas of zone 5 require time to allow the amendments to change the pH.
To have a larger bush that produces more berries, you need to remove all flowers for the plant's first two years. You will go without berries during this time, but the plant's eventual yield will make up for the loss.