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Re: HYB: Daylength independent


I'd like to get more information on these plants. I have most of them
here and they have rebloomed for me,  but never that early, usually in
September.

Are these newer clumps or older very crowded clumps?

When do they normally bloom in spring. Earlier then most TBs? When do
SDB bloom for you.

Do they get water during the hot periods or just before hot periods?

Do they get any stray light from other sources during what would
normally be dark periods. From house window, street lights etc.

My plants are field grown nd have absolutely no extra light of any
kind.

Iris are classified as "long Daylight"  bloomers. They have discovered
that this is incorrect as plants should be classified according to how
much  darkness they get. So "Short Nights" is probably more correct
terminology.  Most plants that are controlled by photoperiod have very
specific and precise  photoperiods  needed to trigger FBI (Flower bud
initiation). Disruption of  the night lighting by even a small amount
can disrupt this sequence.  Plant growers will delay Chrysanthemum
bloom by turning lights on at night for one minute each night until
they reach the time  they want, usually in time to have plants in
flower for Mother's day.

Plants that have had flower bud differentiation ( July/August at
40-50F)  will still need to reach the appropriate biomass (rhizome size
and number of leaves) as well as have the photoperiod trigger. If the
rhizomes are crowded, and not up to size, then they will not bloom.
Normally plants can turn off  the bloom trigger if the plants are not
up to size, but this could be one of the biological functions that are
different.

Most plants will produce a chemical to protect it from hot weather
around 40C (105F) . Even so I have had good rebloom in my unheated
green house, and about 3 weeks earlier then the same cultivar in the
field. (No extra light). The plants in the greenhouse did get good
watering so there wasnbt any water stress, or at least much less then
the field plants.

Give me more info and we will go from there.

Chuck Chapman

Date: Thu, 21 Feb 2008 07:44:06 -0500
From: autmirislvr@aol.com
Subject: Re: [iris] Re:  HYB: Daylength independent

In Kentucky, Immortality, Again & Again, Lunar Whitewash, Feed Back,
Total Recall, Renown, and a few others, including but not limited to my
own All Revved Up, have bloomed in July, August & Sept.? Around a dozen
do so in my garden.? Another dozen if we count seedlings.?

Another very small group will occasionally rebloom in July if the temps
are a bit cooler.?

I'd considered all of these daylight independent since shorter days are
not required to trigger the bloom.?

In the Checklist, these are the irises that are listed (once widely
distributed) to rebloom in zones 4 and above.? Previously called
Everbloomers or Continuous bloomers.? They do neither, but CAN bloom at
anytime, unlike the cylce rebloomers.?

Maybe "daylight independent" is not the correct term for what happens
in my garden, but short days are not required to trigger this bloom.?

These two groups have figured more heavily in my breeding in the last
two or three years.? I anxiously await bloom season.?

Regular rebloom, or cycle rebloomers, dependent on the cool period you
mention, do not start rebloom before Sept. 15, or even Oct 1.?
Our?killing freeze will be mid-october till Christmas, with Oct being
the norm.?



In all cases fertility and water are necessities.?

Although I bought a wide range of older rebloomers when I moved out
here,?only a select few are being moved to the reorganized?beds. I make
no attempt to grow all of anything.???

I do have a good collection of newer rebloomers,?especially the ones
registered,?and hope to be able to report on them in the coming year.?


?Immortality can sit in my garden with mature size rhizomes and lots?
of leaves, but doesn't bloom until Mid to late August. This would?
suggest that it is not daylight independent.?


Betty Wilkerson/Bridge In Time/Zone 6/Dreaming of another good spring.?
"Only those who dare to dream can make a dream come true."?




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