parallel regions

Jane McGary
Sat, 21 Nov 2009 12:36:01 PST
Lou Jost and Diane Whitehead added some interesting climate variables 
to consider. Both mentioned fog, which in coastal and some alpine 
regions provides moisture where there is no rain. There are several 
"fog deserts" in the world, the most notable being in Namibia and 
northern Chile. I don't know if there are any bulbs in Namibia, but 
there are many in northern Chile; however, when it doesn't rain 
(i.e., when El Nino does not occur), many of the bulbs do not appear 
above ground that year. The fog keeps the sclerophyll shrubs going, 
and some of them flower even without rainfall, but it doesn't moisten 
the soil enough for the bulbs to grow.

Diane mentioned "the intensity of winter light in Arizona," and this 
reminds me that I always notice the difference in habit between bulbs 
I've grown in my frames and the same species grown in alpine houses 
in the UK. The latter tend to be taller and "drawn," and I suppose 
this is due to the difference in winter sunlight, since I'm at a 
lower latitude even though it's colder here and often cloudy.

The depth and persistence of winter snow cover, also mentioned by 
Diane, is very important for the survival of alpine species. If you 
have reliable winter snow cover, you should experiment with alpine 
species from many parts of the world, even if you perceive the 
climate there as much warmer than yours. I found this out (too late!) 
when I gardened in Fairbanks, Alaska.

Jane McGary

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