Ask Mr. Smarty Plants

We're afraid we don't know what Poway is, another smaller area of the planned community Rancho Bernardo? Anyway, let us introduce you to a super website, the USDA Hardiness Zone Map. Click on California from the two-letter abbreviations beneath the map, and you will see the zones delineated for the entire state of California. Remember, these are pretty arbitrary, there are no physical barriers between Zone 10a and Zone 10b, for example. It just makes it easier to understand what plants can and cannot live in a particular area. Look at the map of California, looking down at the southwestern corner of California, where San Diego County is, and you will see basically vertical stripes of color. When you compare those to the list of colors and Zones on the left side of the page, you will see that, in that area, the zones range from 10a to 11, with average annual minimum temperatures ranging from 30 to 40 deg. F.