RE: Re: TB: Summer Growth - aphylla, rebloom, late freezes

When we talk about plant response time in iris we are talking about weeks.
The rebloom condition is set up over a much longer period of time, rather
than subject to the momentary or daily climate change.  The plants respond
to the heat as a protection from dehydration....as soon as the temperature
drops down the cells open and away they go again.  You could liken it to the
plants holding their breath for a minute....or so. I don't have information
on specific cultivars as far as stomata response goes....maybe a good
masters thesis for someone.  

We have total recall blooming right now and the blossoms went through the
100 plus heat like champs. Of course I was out there daubing their little
foreheads for all the perspiration...lol.

-----Original Message-----
From: owner-iris@hort.net [o*@hort.net] On Behalf Of Linda
Mann
Sent: Tuesday, July 25, 2006 6:19 AM
To: iris- talk
Subject: [iris] Re: TB: Summer Growth - aphylla, rebloom, late freezes

Interesting, Ross.  Do you know if that is true of all cultivars or is
it somewhat variable?

Mike Sutton mentioned that high temperatures didn't seem to adversely
affect rebloom, but rebloom did seem to be reduced when humidity was
high.

<Over 85 degrees, the plants shut down the openings on the leaves
(stoma),
                        now we have a sealed leaf with no release
mechanism until the air
                        temperature lowers so the stoma can once again
open and release to the open
                        air. "Ross BeVier" >

Aphylla clones that I've planted here were completely dormant in the
summer.  However, they didn't have the root system to handle my gravel
and hot dry summer weather and didn't live more than a few years.

The only reason I tried them was curiosity to see how the species
responded to my growing conditions.  My conclusion was that aphylla
genes alone couldn't survive here. But I think I found aphylla in the
background of everything with the best chance of avoiding early spring
growth/late freeze damage here.  I think that's what I found....don't
have time to rummage thru my notes.  Walter, if what you say about
aphylla being dormant all winter is correct, that matches my
observation... aphylla genes might 'slow down' responses to early spring
(or mid-winter) warmth, giving a better chance to escape damage in
erratic weather..

<I have read that aphylla is dormaqnt in the winter and grows all
summer.           From: Walter Pickett <waltseed2@yahoo.com>
--
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/>
photos archives: <http://www.hort.net/lists/iris-photos/>
online R&I <http://www.irisregister.com>

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