global warming

Helene,

The way your plants are acting now is what we get almost every year in
southern California.  All year we regularly experience such fluctuations in
temperature that the plants are perpetually confused and don't know how to
act.  Most plants are genetically programmed by prevailing light cycles and
temperature gradients in their native habitats.  Transplanted to another
climate where seasons don't match the ones they're used to screws up their
internal clocks.

Here, our weather is a constantly surging battle between desert and coastal
influences.  When there is high pressure over the inland deserts of Nevada,
warm (or hot) Santa Ana winds blow through our passes and canyons, carrying
away smog and keeping coastal fog offshore.  (This is equivalent to your
Sirocco, which blows when high pressure sits over North Africa).  This can
happen at almost any time of year, but the strong difference in temperature
gradient in winter makes it happen more often now.  When the high pressure
cell moves on to the east, it draws in the coastal breezes and fog and cools
us down.  This see-saw happens all year long, and it keeps plants guessing.
After living here for thirty years, I have come to accept that no year's
seasons will be like those of any other year.

Global warming does seem to be real, but just how much and how it will
change local climates remains to be seen.  Even the experts disagree, and
only long range hindsight (exceeding our own brief span of years) will give
any definitive answer.  One, or even several, unusual seasons are no real
proof.  The Midwest and Northeastern U.S. have had three relatively mild
winters in a row--last year was the warmest on record--but now they are
knee-deep in snow.  Even with clearly discernable long-range trends, yearly
fluctuations are inevitable.  Even if the climate were not warming
significantly, Rome would be bound to have an unusually warm winter once in
a while.

All I can say is, enjoy it while it lasts, and keep your eyes open.
Observing how plants react to different conditions can always be
entertaining and enlightening (if sometimes saddening).  Whatever the
weather is now and for whatever reason, it is sure to change, and we won't
have much say in the matter.  We just try to make the best of it.

John MacGregor
jonivy@earthlink.net
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