Answer: Usually, when people talk about zones, they are referring to the US Dept of Agriculture (USDA) zone map. This map divides the country into zones, based on the average lowest winter temperature. Your USDA zone is one way to help determine which perennial plants will survive in your region. Since climates vary widely--even within the same USDA zone (for example, one zone 8 region might be in a rainforest, while another is in a desert)--the zone information is just one tool in choosing plants.
The USDA zone map works best in the eastern half of the country. In the west, the variables--elevation, rainfall, etc.-- that affect a plant's ability to thrive are more extreme. Therefore, many western gardeners use the Sunset Western Garden Book's zone system. You might find this book a very valuable resource as you pursue your gardening hobby. Also, neighbors who garden are a great source of information--they have first-hand experience about what grows well in your region.
You are in USDA zone 7, and Sunset zone 2.
Q&A Library Searching Tips