Nonetheless, gardeners in Orange County can't grow a decent peony, lily of the valley or aspen tree. Don't zones have something to do with this?
In 1960, the U.S. Department of Agriculture published its first zone map. A few years later, it was significantly revised. In 1990, in cooperation with the National Arboretum, the USDA updated its zones again. The USDA uses a one-to-11 numbering system, which is further divided into A's and Bs.
In 1967, after 30 years of publication, "Sunset Western Garden Book" introduced its own plant zone system. Likewise, "Sunset's" zones have been revised several times, essentially every time a new edition is published. Sunset's zones are numbered from one to 24, but recently five more zones were added to cover Alaska and Hawaii.
Are you confused yet?
The point of all this zone stuff is supposed to let you know what plants you can grow in your yard and which ones you can't.
It's a simplistic shortcut to a complex topic. Gardeners, like most people, like simple, straightforward, black-and-white answers. Here's another overly simplistic shortcut — a 15-30-15 fertilizer is a better value than a 5-10-5 fertilizer, right? Not necessarily.
At best, plant zones are a guide.
Probably, everyone reading this column is, according to the USDA, gardening in zone 10A or 10B. If you're a "Sunset" reader, you're almost all gardening in zone 24. This is certainly true of the communities of Huntington Beach, Costa Mesa, Newport Beach and Corona del Mar. A handful of residents in the canyon bottoms of Newport Coast might drift into zone 23 or even 22.
Now that you know your USDA and "Sunset" zone, plant selection will be simple, right? Not exactly.
