Re: CULT: cold

That is only my 'worry' temperature here - like you say, if it's been
frosty or at least not warm and balmy, those temperatures do a lot less
damage than otherwise.  I've noticed that temperatures <above> 25
degrees F usually don't do much damage, even to buds showing color, <if>
it hasn't been warm and soupy out.

And there are <so> many variables, my cutoff temperature may not apply
other places. For instance, the gravel soil warms fast, the hill behind
my house blocks the sun till late in the morning, the garden's wide open
western exposure warms things up too soon, plus this is a valley, so
this is where the coldest air settles.

Plus the stage that irises are in probably makes a difference.  I don't
know much about physiology & development, but seems like I remember that
undifferentiated tissue (meristem etc as in developing stalk/flower bud)
is more susceptible to damage at certain stages of development. Not like
leaves that are made of cells that are already leaf cells.

As for damage, leaves on some of the plants that didn't get covered have
that dessicated look - still green, but sort of pale and unhappy
looking.  No major damage to foliage showing so far.

Now for the big <but> - I have several cultivars that have wonderfully
healthy foliage after the worst of freezes, but lose their terminals and
do not bloom without protection from these late March freezes.  RIP CITY
is a good example.  TITAN'S GLORY is another.

Neil said:
<Boy, Linda.  If you are right about 25 degree cut-off, then I can
expect a
                   whale of a lot of damage.  My outdoor thermometer
(uncalibrated) showed 18.8
                   degrees minimum Monday morning.  We had dropped below
32 soon after sundown,
                   so there were looooong hours of freezing temps.....

Irises showed little damage from temps deep into the lower 20's even
right into bloom
                   time if they had adequate time ahead of the freeze to
chill.>

< Apparently there is a natural "antifreeze" character in plants
.....Bearded irises seem to
                   have this ability right along with pansies and winter
cabbage..  Neil Mogensen  z  7  western NC>



--
Linda Mann east Tennessee USA zone 7/8
East Tennessee Iris Society <http://www.korrnet.org/etis>
American Iris Society web site <http://www.irises.org>
talk archives: <http://www.hort.net/lists/iris-talk/>
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