Re: Summer bloom

It definitely would seem that at least for summer rebloom that there is a critical number of mature leaves for each cultivar. This would seem to also be connected with warm nights for flower bud initiation. any where from 3-7 nights with minimum above 15c , again seems to vary from cultivar to cultivar.
Of course plant needs to be biological active. That is being warm and having access to moisture And max temp in day to not be above the critical (for cultivar) of heat dormancy, of about 102F . 

Extra light allows plant to continue growing.
Some more observations. I had rebloom on one fan of Blessed Again. I checked this out in more detail. Flower stalk was on a fan that hadn't bloomed in spring. There are lots of fans with 11 leaves but no bloom. this would sem to be a Fall rebloomer and is probably waiting for short daylight to trigger further rebloom.
Seedlings that bloom for firrst time in summer have gone through a winter vernalization. Thus they are pre-prepped for bloom. Thus they can bloom as soon as they have flower bud differentiation. Thus summer bloom does not mean that they are summer rebloomers, and may not be able to do so again. They may or may not have the genes that enable bloom without vernalization.
According to literature, there are two different genes controlling vernalization. Those that bloom in summer could have one modification and those that bloom in fall a modification to the other gene. I will need to review literature to sort this out further. 

Chuck Chapman


Date: Sat, 30 Aug 2008 07:40:33 -0400
From: Linda Mann <lmann@lock-net.com>
Subject: [iris] Re: Summer bloom

["summer" as opposed to fall cycle]

Chuck, with so few stalk fans to count for comparison so far, maybe I'm
jumping to conclusions here, but I'm wondering if there is a constant
ratio between green leaves on blooming vs non-blooming, even tho the
actual number of green leaves might vary from cultivar to cultivar and
under different growing conditions.

I've been counting leaves on maiden seedling fans, wondering if those
with 11 green leaf blades in the main fan might bloom this fall (or
could if water/nutrition/temperature allow it).  This is the first year
with a <lot> of unbloomed seedlings from various rebloom backgrounds,
most from crosses with 1/36 probability of rebloom, some even less.

The clump of IMMORTALITY fans is conveniently located to observe and
take notes.  I may even tag each fan with a leaf blade count and try to
keep track of how they change between now and spring bloom when things
get too hectic to make observations.

- --
Linda Mann east Tennessee USA zone 7/8

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