Pruning Azalea Back in Late Fall

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New York City
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#1
Hi all, I'm specifically wondering about a kiusianum azlaea. I have a very limited overwintering space, so I'm wondering if it's safe to prune back a leggy azalea before storing for winter? I know you're supposed to prune back after flower drop in spring, but is this ever an acceptable practice? Or would it have negative results come springtime? Thanks!
 
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Richmond, VA
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#2
Pruning that late will sacrifice some flowers for the coming spring, but if you don't care, go for it. Major or hard pruning late in the season could also cause some winter die back in a lot of different trees. If you're just wanting to prune runners or leggy growth, it will probably be fine as long as it's not a significant amount of growth.
 
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New York City
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#4
If you're definitely pruning back hard, I'd do it now. If you're just cutting back a few runners, you can do it later in the year.
Well, next spring I was planning to prune back hard, basically to a stump. This winter I just want to make it easier to store. I don't care about flowers next year, so I think I'll cut back relatively hard, but nothing crazy. You think there's still time for buds to grow and harden?
 

Dav4

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North Georgia/lived in MA until 2009
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#5
Well, next spring I was planning to prune back hard, basically to a stump. This winter I just want to make it easier to store. I don't care about flowers next year, so I think I'll cut back relatively hard, but nothing crazy. You think there's still time for buds to grow and harden?
The tree will be fine with a hard cut back now... can't comment on flower buds, though.
 
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Milwaukee WI
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#8
Broadly—and I mean very broadly speaking, true azaleas [Satsuki and otherwise] at approximately 40 degrees latitude [plus or minus six] will start to come out of dormancy about one lunar cycle before the vernal equinox, and begin to bloom two lunar cycles thereafter. [roughly February 20-something to start waking up, and late May to begin blooming]. After another lunar month, the summer solstice, whether or not they are done blooming, they will begin to push new growth, which will set flower buds until the autumnal equinox. After that, it’s pretty much what you see is what you’re going to get.
In other words, if you care about flowers in the upcoming year, you can expect that whatever vegetation you leave on after the Fourth of July will produce flower buds. You can prune to shape after that time, but whatever you cut, if it buds back, cannot be relied upon to produce blossoms the following spring. Of course all of this is subject to local conditions, and whatever weird weather you have that year [knowing that climate change is a Chinese hoax to perpetuate their trade advantage].
Based on my recent experience with both Satsuki azaleas and rhododendron azaleas, chopping the crap out of them tends to incite more rapid and robust budding—albeit with a two week lag—than mild pruning does.
 
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#9
I would do a hard cut in spring. If you time the hard cut right and if the hard cut is as hard as possible, you will get the most backbudding on old wood, assuming that is what you want.
 

GrimLore

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#10
I know you're supposed to prune back after flower drop in spring, but is this ever an acceptable practice? Or would it have negative results come springtime?
In general -

The plant is well suited to your Zone.
It is Post Bloom.
There appears to be some growing season left in these parts.

IF there is still 3 weeks or more before the HEAT WAVE that causes dormancy for a couple of weeks in the Northeast it is safe to cut it back ASAP but leave some foliage on all branches being cut. It will or should back bud a bit and throw some new foliage at you before that time. It will handle the dormant period and Winter OK if so... Regardless it will be overall "smaller" but a survivor. Having handled a lot of types here in similar climate it is the best I can tell you. I would do that and the heavy cutback post bloom early Spring to insure overall health. Cutting back and going into the Heat wave to early will harm, perhaps kill it. Been there, done that, and for the record in NY as well, not pretty.

Grimmy
 
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New York City
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#11
In general -

The plant is well suited to your Zone.
It is Post Bloom.
There appears to be some growing season left in these parts.

IF there is still 3 weeks or more before the HEAT WAVE that causes dormancy for a couple of weeks in the Northeast it is safe to cut it back ASAP but leave some foliage on all branches being cut. It will or should back bud a bit and throw some new foliage at you before that time. It will handle the dormant period and Winter OK if so... Regardless it will be overall "smaller" but a survivor. Having handled a lot of types here in similar climate it is the best I can tell you. I would do that and the heavy cutback post bloom early Spring to insure overall health. Cutting back and going into the Heat wave to early will harm, perhaps kill it. Been there, done that, and for the record in NY as well, not pretty.

Grimmy
Ah, thanks, Grimmy. So I'll do some light pruning now, and then the heavy cut back next spring. Much appreciated.
 
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Milwaukee WI
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#12
I went back and re-read your original question. If what you're asking is about late-season pruning to make the tree smaller, to better fit in the small space to which you refer, cutting leggy growth off will obviously eliminate the stems and the flowers they would otherwise have carried into spring. It will not, though, have any deleterious effect on the foliage--and associated flower buds--that remain.

If you are fortunate enough to lay hands on Callaham's book on Satsuki's, there is a fascinating section on the process of bud formation, including an explanation of how embryonic buds of only a few cells will spontaneously mutate when hit by gamma rays. Relative to a lot of other plants, their genetic mechanism for controlling the color of the blossom is weak, perhaps in part because of 500 years of hybridization. More than any other member of the rhododendron family, they have a propensity for polychromy. I have an eiga-no-homare that will throw solid white, solid pink, bifurcated, and speckle-throated, all at the same time. [Callaham's book is worth its weight in gold, BTW. Your local club library may have a copy to peruse.]
 
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#14
I don't think there is definite research on this specifiically for tsutsuji rhododendron, but I am pretty sure that colour variation in azalea is caused by jumps of transposons. If they jump in or out of a reading frame of a gene responsible for the color (be it the color compound creating enzyme itself, or something indirect), then the color will or will not be produced. So not a point mutation caused by maybe gamma rays or something else, knocking out a essential colour gene. In that case, the odds of a gamma ray by accident repairing a broken gene are many times smaller than turning off a gene. And in satsuki we see color turn on more often that color turning off. Solids with white streaks are rare.

Check 'Flower color variation: A model for the experimental study of evolution' .
 
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Milwaukee WI
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#15
I have no reason to doubt your observation. I work in investments, and am only just beginning to try to understand some things about genetics. At the moment, I'm laboring my way slowly through Kobayashi's "Evaluation and Application of Evergreen Azalea Resources of Japan". I'm good for about five or six paragraphs before I get a cramp in a frontal lobe and have to put it down for a while.

Knowing that Callaham was writing in 2006, and the explosive rate of progress in recent genetic research, I'm sure much has changed in the interim.
 

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