Hardiness

Kenneth Hixson khixson@nu-world.com
Tue, 28 Dec 2004 07:36:41 PST
Dear members:
         I apologize--obviously I wasn't clear.

>I'm still not sure whether tender bulbs that are in growth would do best 
>being watered before you know a cold period is coming or kept dry.
         "Tender" is a relative term--just as the lilies could tolerate 
being frozen--
or flooded--while dormant, they do not tolerate being frozen when making
new growth and are "tender" when doing so.  A month earlier they weren't
tender, and a month later they probably wouldn't be.  Bulbs being watered or
not being watered is probably irrelevant, except for one thing:  At least 
in some
areas, irrigation systems are sometimes used to provide frost protection.
Ice may freeze on plants from the irrigation water, but the plants, even if in
flower, may survive several degrees below freezing.  Probably no more than
ten degrees (F), and only for a few hours.  An extended freeze will cause
damage even when the plants are encased in ice--but the damage will be
from cell rupture, not "burning" from moisture loss from leaves.  One cause
of damage was prevented, but not another, and the plants were damaged.
Thus, whether or not being watered has an effect on a "tender" plant
depends on circumstances, including the timing of watering.
         Plants not exposed to sudden warming by morning sunlight are
less likely to be damaged than plants which are exposed.  Borderline
tender plants will often be successful in a north or west exposure, while
the same plants in an eastern exposure will be killed, even if only a few
feet apart.

>It is very possible that it is different for shrubs, trees, perennials, 
>and bulbs.

         By one definition, all of the above are perennials.  They have 
different
ways of dealing with inclement weather, not only freezing, but extended
drought, etc.  Some bulbs try to evade or mitigate the effects of freezing,
or drought, by growing at another season of the year.  Or they become
dormant, even though still leafed out, etc.  Each plant has a unique way of
dealing with unfavorable conditions, and different ways at different times
during its' growth cycle.  There are supposedly some algae which can
survive and grow  within polar ice caps.  Whether a particular plant can deal
with a particular stress depends on its particular growth condition at the
specific stage of growth.
         About all you really can say is, a "tender" plant will be---tender,
because that is what you have defined it.  You probably defined it as
"tender" because you knew it would not survive normal conditions in
your area, even if you do not really understand exactly why.

         Again, I apologize for not being clear, but there are many things
happening in plants which we humans do not see or understand,
and can only say "This is what happened under these particular conditions,
and if they keep happening, I assume they probably will happen in the
future under similiar conditions".  Being "tender" is one such condition.

         Ken


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