RussM,
The USDA climate zone map is just a guide. Each person/property can have micro-zones that differ. In my yard I have seen anywhere from zone 8a to 9b depending on exactly where something is planted.
May I inquire what is your zip code/state/city? There are places you could get more accurate information for your exact location such as your local County Cooperative Extension Service or a local farm/feed store, but not knowing your location I cannot give you more details.
