"Hey, baby, what's your.......... ummmm, ¿zone? Seems we gardeners have a language all our own, and what an icebreaker, huh? Ask any gardener, and they seem only too happy to share, but what are these zones, really? Are they the horticultural rosetta stone for unlocking the key to this fine hobby of ours, or are they simply a tool so overused and magnified in importance as to be rendered all out of proportion to their real significance?

 The zone system was originally set up by the u.s.d.a to chart typical winter low temperatures throughout the gardening world. Why low temperatures?  Well, there is nothing quite like cold to ruin a perfectly good plant. Ruin, as in dead. Various plants have the ability to withstand varying degrees of cold -- the term for this is "hardiness" when applied to plants -- and the system was set up to help gardeners avoid planting those plants that would only perish with the arrival of their typical winter.

"Typical" -- well no winter is typical, of course, but the system is based upon the statistical likelihood that a certain low temperature will be achieved in any given winter. These temperatures were then divided into ten degree increments, and assigned numbers, with the lower numbers having colder winters, with the higher numbers being milder. They are hardiness zones -- no more, no less. They help determine a plant's chances for survival in *winter*, and that should be the limitation for their use -- just a simple guide for charting plant hardiness.

There do seem to be quite a few common misconceptions about the U.S.D.A. zones, though. Perhaps it is because we rely on them like we do that we seem to think they mean more than they really do. Here are a few of these misconceptions:

That these are climate zones.  Wrong  Low temperatures are just one aspect of overall climate, and there can be several different climates in one zone. Zone 9, for instance includes Mediterranean, Desert, and Humid subtropical climates, and each has quite different characteristics. These are not different microclimates -- they are different climates.

 That higher zones have warmer summers -- those "Hot summer zones" Wrong.  There is no correlation. People living on the Scottish coast would be quite startled to know that because of their relatively high zone number, they would somehow be considered to have hot summers. It is true within interior continental areas, where many people live, that higher zones have warmer summers, but in many maritime areas, the very reverse is true, and milder winters are associated with cooler summers due to the moderating influence of the ocean.

 That people living within the same zone can be expected to be able to grow the same plants..... Wrong. A quick visit to the British Columbia coast, followed by a trip to Western Texas would dispel that myth. These two places share the same zone. There is really no such thing as "zone such and such" plants in these instances.

 That experiencing occasional colder winters means that a person lives in a lower zone. Not necessarily. Our normal winters here in the Willamette valley of Oregon usually hit the +10-20 range, placing us in zone 8. In 1972, we approached -10. That doesn't mean we are really two or more zones colder, only that we experienced some unusual weather. It is only when the microclimate of a certain area is consistently colder than their surrounding area that there might indication they are in a colder zone.

As has been pointed out, these zones only take into account average winter lows, and in fact, often have little to say about the actual winters even, other than this fact. Our average winter highs are ten to fifteen degrees or more lower than similar zones in the south, and we far colder overall in winter. As a result we can grow many more plants requiring a cold period, as they get their chilling requirement.

 So what does this all mean? Simple, really. If the question of winter survival is of importance in relation to a plant, knowing the zone is *very* important. Otherwise, well, ....... it's always a good conversation starter........