Re: REB: CULT: rot
- Subject: Re: REB: CULT: rot
- From: L* M*
- Date: Fri, 20 Apr 2001 17:53:28 -0400
Iris Moose said:
<My biggest fear is that dreaded "Rot" that I hear so much about with
irises.
What are the main causes for rot? Also, more importantly, what is the
best
way to keep the rot characteristic out of a breeding line? >
Main causes are stresses and can include poor soil drainage and poor air
circulation; too much rain; too much rain after drought; heat; high
humidity; damage from just about anything including insects, varmints,
sudden hard freezes after warm spells in the middle of winter; too much
lush growth from too much nitrogen;...., .. Probability of rot depends a
great deal on where you live and what kind of soil you have as well as
how you treat your irises and which cultivars you select, combined with
how obnoxious the weather is any particular year & season.
Different cultivars respond to these different stresses differently -
for example, some can take lots of rain, some can't; some handle the
sudden hard freezes in the middle of warmth, some can't.
G.P. Brown introduced some supertough rebloomers that Don and Ginny
Spoon at Winterberry Gardens sell. They are not modern but you are
young enough that you might be able to work some of those genes into
your breeding program.
Most of the recently introduced rebloomers I have tried are a compromise
between improved appearance and toughness. I bought some of the Brown
intros a couple of years ago and have been really impressed with their
performance here. A line of better looking rebloomers with the
durability of those irises would be wonderful for this part of the
country. You are east of the mountains where the weather ups and downs
tends not to be quite as severe as in the middle part of the country.
I don't know how to keep rot susceptibility out of your breeding lines
other than sending seedlings off to a harsher environment for trial. Or
do as I jokingly suggested to Mike Sutton a few years ago - grow your
irises in pots, then when they are growing like mad in early spring,
about a month or two before you expect bloom, put them in the deep
freeze overnight and see how they fare.
We've had a lot of discussion about probabilities of heredity of
different colors and patterns, and about inheritance of rebloom
probability, but it seems not much is known about heredity of
sensitivity to different sources of stress since they are so different
in different regions and even from one garden to the next within a few
miles of one another. Then there is the problem of hard freeze damage
to actively growing irises looking like scorch or something wierd in the
soil.
Thanks for posting all the info you recieved offlist. Iris Moose??? Is
that really your name?
Linda Mann east Tennessee USA zone 7/8
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