Hi Annette, Yes, zone 6b came from your zipcode base on the 1990 USDA Hardiness Zone map. This map is admittedly out of date, since it was made before the new climate models based on global warming. Arbor Day made an updated Hardiness Zone map in 2006, which has a zipcode look-up here: http://www.arborday.org/treeinfo/zonelookup.cfm This map says you are in 6 or 7. We are currently testing a feature that allows you to set your Hardiness Zone as you wish, so look out for that update soon, under My EasyBloom :: My Profile. Hope that helps! Matt