Northern Spy has thin skin and very crisp delicious flesh with a sweet/tart flavor prized for cooking and fresh eating. It is among the best keepers. It is winter hardy. These outstanding qualities make many people throughout the U.S. grow it despite it being biennial and taking a few extra years to come into production. It blooms late in the spring and ripens in November making it too late to fully ripen in cooler parts of the Pacific Northwest. USDA Zones 4-9.