1936 usda zones, US

Norman Woollons normanwoollons@gmail.com
Sun, 07 May 2017 18:27:44 PDT
The USDA system is often quoted because it is better known than Köppen and
breaks a huge continent down into more convenient blocks.  Plus there are
websites where by entering a zip code you get your zone.

I also use Sunset where my Mediterranean home equates to a zone 21, but
that is only a rough equivalent because I live in a thermal belt on a north
facing hill, on an island in a warm sea.  So I am in Köppen CSA, USDA 10A,
Sunset zone 21.  But my weather station records 3 to 5 degree Celsius
temperature differences between the different orchards, 5 sensors in all,
where I have planted bulbs between the trees.

Hot, dry summers are the Mediterranean signature, but few systems take
these climatic conditions into account.  All systems rely on extensive
records going back tens of years, but our current planet wide weather
pattern instability, is too recent to feature or be factored into the
published zoning information.

Much of what I plant is experimental because whilst there are many books on
Mediterranean gardening, they focus almost exclusively on areas where there
are "gardens", Spain, south of France, Greece, Cyprus etc..  This is an
area where few decorative plants are kept.  My neighbours use every square
inch of space around their homes for edible crops, so I can't look over a
wall to see what they have.

I look at what the advice is for a bulb (or tree, plant, shrub), see if I
have somewhere which replicates to any degree the conditions it tolerates
and try it..  So in the colder microclimates my Iris have put on a
wonderful show this year but are now almost finished, in warm corners the
tropical  Spider lilly, Hymenocalis is growing well, and the fox tail
lilies are looking good.

I think I do what probably everyone on this list does, I use the zone
information as a guide, then my experience of living in different countries
and my knowledge of plants, and my own continually evolving knowledge about
my microclimates, soils erc to find them a corner where they may thrive.  I
have a lot of success, but also failures, which I accept. It is the weather
aberrations which catch me out.

NW

On Sun, 7 May 2017 23:17 Jane McGary, <janemcgary@earthlink.net> wrote:

> One problem with the USDA zones, as Bob notes, is that they do not deal
> well with steep transitions from one elevation to another. As a result,
> my former property in the foothills of the Cascade Mountains was on a
> border between Zone 8 and Zone 1. Another reflection of the fact that
> these zones were drawn up east of the Rocky Mountains, where a lot of
> the country is relatively flat, and intended originally to help growers
> of fruit trees. Eventually Sunset Magazine, a California publication,
> took the matter in hand and made a new, much more complex zone map for
> the American west.
>
> Though now in "Zone 8," I rarely choose plants with that zone rating
> because I'm pretty sure they will be killed in one winter in four.
> Moreover, zone ratings based on winter lows are inadequate: summer
> atmospheric humidity is also an important factor in plant survival
> because it affects the differential between daytime and night temperatures.
>
> Jane McGary
>
> Portland, Oregon, USA
>
>
> On 5/7/2017 10:29 AM, penstemon wrote:
> >> Bob posted a link to a photograph of a USDA climate zone map from 1936.
> > Were the temperature ranges for each zone the same then as they are now?
> > It was Rick’s link. It doesn’t seem to matter what the ranges were.
> > Much of the northeastern US is shown in the same zone as some of the
> more frigid parts of Colorado. (Extreme northwestern Colorado.) If that
> were true, then much of New York, northern New Jersey, and western
> Connecticut would be devoid of much of any vegetation, because of the
> continual drops in temperature to –50F (-45.5C) and below.
> > We probably would have read about that at one time or another.
> > Bob Nold
> > Denver, Colorado, USA
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