Hardy Arisaema growing conditions-- long post

[Scott Vergara]

Greetings All,

Jim W. brings up a point that I would like to put a slight spin on.  IMHO
there is a tendency to put all the emphasis on winter lows and not consider
that average summer temperatures (including highs) play an important role
in the survival of a plant.

There have been some studies done to indicate that the temperatures a plant
experiences influences specific carbohydrate synthesis as well as total
amount of carbohydrates that a plant stores.  In mild winter climates like
the West Coast of the US, many plants that thrive in similar winter
temperatures elsewhere, or ever colder, do not do well for us.  The
research indicated that the plants may suffer from severe carbohydrate
deficiencies by spring since they are metabolically active during the
dormant period.  This is more of a problem for plants with foliage present
above ground in the winter.  The tubers of Arisaema and others are
potentially more at risk from drowning, especially this year.

High elevation species that experience cool nights during the growing
season do very well here but those that need high night temperatures
usually do less well unless grown in a hot spot in the garden.

This was brought home to me when I visited with the late JC Raulston
several years and visited his garden and noted that many geophytes grew
very well out in the open garden there, and were at best a challenge in the
Seattle area.  JC and I talked about this photosynthesis,/carbohydrate
situation and the lack of vigor in many warm climate species when grown in
the cool PNW.  I don't recall where any research is published but some
plant physiologist in the group may remember.

Thus, I think it is important to discuss the summer temperature profile as
well as winter lows and the snow cover mentioned by several others.

People melt here when the day temps go above 85F and many summers I sleep
with a quilt all but a few nights.  Some summers, our daytime highs are
lower than much of the East Coast US night time lows.
I make lots of green tomato chutney and relish.

Best Regards,

Scott

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Scott Gregory Vergara
Botanical Resources
(Specialty Nursery, Horticulture Education/Training, Consulting)
P.O. Box 669
Burley, Washington  98322-0669   USA
USDA Zone 8 Ave Min Temp 10-20 deg F. Record low 0/hi 104
svergara at pacific.telebyte.com,  HORTULANUS at aol.com
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