Different rebloomers do different things in different climates.
Immortality is almost always the first of the TBs to rebloom here, but
never before mid August. It does not show any characteristics of
daylight independence for me in my climate and not for anyone else in
this climate. A cross of Immortality X Forever Blue produced a bunch of
dogs, but no rebloomers of any sort.
There are various biological
triggers for flower bloom. I've been
collecting some refferences but
haven't read any of them yet.
I can't remember how many, but enough to be
sure of my observations. I
also had a number of crosses with other relible
early and cold weather
rebloomers, all with the same result. Whatever it
is with Forever Blue,
it is different then what is causing rebloom with
other rebloomers.
The cross with Victoria Falls is the only cross with TB
that has
produced rebloom. Most crosses with other SDB rebloomers X
Forever Blue
gives the same story. The Exception was the cross with What
Again,
which produced 90-100% rebloomers, all of the Daylight independent
type., that is reblooms whenever. They all did not show the very early
rebloom that is characteristic of those that I introduced, Forever
Violet, Blueberry Tart etc.
I have never seen anything from
Immortality (or any other TB) that I
would call Daylight independence. The
only other plant that shows
similar rebloom is the IB Precious Little
Pink.
Iris are generally triggered by the number of hours of daylight ,
coupled with all the other triggers of spring growth. They also need
the cold period to set next years bloom (estivation). Lloyd pointed
out
to me that I could get a lot of rebloom that he didn't as I had colder
nights in the summer. This would suggest that a number of rebloomers
can get away with a temperature differential much less then the cold of
a full winter. These plants still seem to need the daylight triggers.
Artificially giving longer daylight (light supplements) will increase
rebloom. Sometimes a plant will have an bloom triggered in a rhizome,
but it will not have sufficient trigger size in spring to set off
bloom, even through it will respond to the daylight hours of spring.
This rhizomes will continue to grow until it reaches size to produce a
flower. This can appear to be daylight independent, but it isn't.
Trigger size is my own concept. It referees to the size of the rhizome
needed to support a bloom stalk, in terms of plant energy. I would
suspect that a lot of rebloomers have a small trigger size.
The
hours of daylight to trigger a bloom can be very specific. I once
rescued
some daffodils in the spring, just as they were starting to
grow. Some of
them went into the garage for awhile . They didn't get
planted for a
while, but took off when planted and had extremely good
plant growth and
it didn't die off like other daffodils did. Then in
Fall, as the daylight
hours decreased, it went into bloom, triggered by
the length of daylight
hours.
Forever Blue is an extremely strong grower and it can produce
trigger
size rhizomes in a shorter time then most plants. These rhizomes
do
seem to need cooler evenings to produce an embryo bloom stalk, and it
does not seem to need a daylight trigger to start this bloom stalk,
only the size and perhaps cooler evenings.
Immortality does seem to
need the daylight trigger for the new rhizome
rebloom. This is different
then late spring bloom as the stalk was
triggered but rhizome had not
reached trigger size. This does not seem
to happen in southern Ontario.
Perhaps because of the later spring.
This would mean that the plants have
had a bit more time for the
underdeveloped rhizomes to get to trigger
size. One of the sine non
quoin of bloom is the ground/air temperature.
Plants can grow in colder
temps, but it is needed to set off bloom stalk
growth.
Again, I repeat, Ihaven't seen any TB rebloom here in Southern
Ontario that would seem to be Daylight independent. They all rebloom in
corespondence to spring daylight hours. Other people have reported
summer rebloom, but I suspect other reasons. and causes to trigger
rebloom, just not known
Chuck Chapman
Re: Hyb: Daylight
Independent
Posted by: "Autmirislvr@aol.com"
Autmirislvr@aol.com
Fri
Feb 15, 2008 3:56 am (PST)
A few hybridizers are working on this trait
in TB
rebloomers.? Constantly searching for irises that bloom in the
summer.?
>
Like other traits it is stronger in some irises
than others.?
Chuck, how many seedlings did you bloom from Forever Blue
x
Immortality??
Betty W/KY/zone 6
-----Original
Message-----
From: irischapman@aim.com
To: iris-photos@yahoogroups.com
Sent:
Thu, 14 Feb 2008 10:16 pm
Subject: [iris-photos] Re: Hyb: Daylight
Independent
The lenght of daylight hours triggers bloom in many plants,
including
Iris. Thus they bloom in spring and again in fall when the
lenght of
daylight hours match the trigger daylenght in spring (for
rebloomers).
Forever Blue and a number of it's children don't need that
trigger, but
bloom whenever a rhizome gets lare enough to support a
bloom stalk.
Most SDB rebloomers rebloom her very late in Fall, just
before killing
frost. This reflects daylight hours that trigers spring
bloom. FB and
its children bloom when ever, and thus rebloom in very
cold regions.
and troughout Summer.
Chuck
Chapman
__________________________________________________________
More
new features than ever. Check out the new AIM(R) Mail ! -
http://webmail.aim.com
