"kaolin and milk" -- sounds like a facial product...
OK, WHERE did I get my ideas from??? At this point, I'm not sure if I can pin point the source -- I read from all over, books and internet -- I really should take better notes... but I'll try.
A lot of the sources that talked about late Fall, etc. I think the authors were from milder climates like California, England, France. I was a bit hesitant, but I really thought the leader and some other branches had to go. Also, I decided to espalier some of the newly purchased fruit trees, so summer
pruning was another technique I was working from.
The Pruning Book
by Lee Reich
OK, I think the critical reference is in pp. 25~26 excerpts:
How a plant responds to pruning depends not only on how much you cut off a stem, but also on when you do it. ... stored food also fuels the growth of the following season's new shoots and leaves... When you prune a dormant plant, you remove buds that would have grown into shoots or flowers ... food reserves ... are reapportioned ... to support growth of more buds ... with increased vigor.... As the growing season progresses, response to pruning changes ... later in the growing season ... Under certain conditions, summer pruning ... can prompt the formation of flower ubds rather than new shoots... Although immediate regrowth rarely occurs after late summer or autumn pruning, cells right at the cut come alive to close off the wound. Active cells are liable to be injured by cold weather... avoid pruning in late summer or autumn except in climates with mild winters or with plants that are very hardy to cold.
Also mentions no late spring or early summer pruning of apples in fire blight prone areas.
Pruning Made Easy
by Lewis Hill
This might've been th one that said "no later than Labor Day"... Hmm or it might've been one of the old Organic Gardening mag articles.... (I hope I'm not confused about that because I can't find it in my notes
Oh, wait, I found it -- "One reference emphatically recommends against pruning after Labor Day because the trees will expend their energy into growing new shoots which will not be winter hardy and in all probability will be winter-killed." -- doesn't say where it came from though.
On p. 26 there's a box discussing when to prune. You can see it on Amazon's look inside if you search for "when to prune" https://www.amazon.com/Pruning-Made-Easy-everything-Illustrated/dp/1580170064#reader
Success with Oganic Fruit
Late Summer Pruning... The tree will be stimulated to set more flower and fruit buds and fewer branch and leaf buds the following year. By removing branches in late summer, you will cause far less regrowth than you would in late winter.
by Yvonne Cuthbertson
Describes "late autumn to early spring" pruning of apple trees.
by Rosalind Creasy
American Hroticultural Society Pruning & Training
I notice I went out and did the November pruning after reading this book, but I don't have notes on why. I found a page of notes started for this book that abruptly ends. I have the feeling I dropped everything and went out and pruned...
ON-LINE: don't know what's what but here are some links I saved
DEP: Rejuvenating Apple Trees Fact Sheet
University of Delaware Cooperative Extension, Kent Co., Commercial Horticulture Information: Landscape - Pruning
Training and Pruning Fruit Trees
Dormant Pruning vs. Summer Pruning
Trees respond very differently to dormant and summer pruning. Dormant pruning is an invigorating process. During the fall, energy is stored primarily in the trunk and root system to support the top portion of the tree. If a large portion of the tree is removed during the winter, while the tree is dormant, the tree's energy reserve is unchanged. In the spring, the tree responds by producing many new vigorous, upright shoots, called water sprouts, which shade the tree and inhibit proper development. Heavy dormant pruning also promotes excessive vegetative vigor, which uses much of the tree's energy, leaving little for fruit growth and development.
Historically, much of the vigorous, upright vegetative growth has been removed during the dormant season; heavy dormant pruning results in a yearly cycle with excessive vegetative growth and little or no fruit production.
Timing of dormant pruning is critical. Pruning should begin as late in the winter as possible to avoid winter injury. Apple and pecan trees should be pruned first, followed by cherry, peach, and plum trees. A good rule to follow is to prune the latest blooming trees first and the earliest blooming last. Another factor to consider is tree age. Within a particular fruit type, the oldest trees should be pruned first. Younger trees are more prone to winter injury from early pruning.
Summer pruning eliminates an energy or food producing portion of the tree and results in reduced tree growth. Pruning can begin as soon as the buds start to grow, but it is generally started after vegetative growth is several inches long. For most purposes, summer pruning should be limited to removing the upright and vigorous current season's growth; only thinning cuts should be used. To minimize the potential for winter injury, summer pruning should not be done after the end of July.
This is where it get's confusing "not ... after the end of July" -- but this is from North Carolina. I've noticed you REALLY have to pay attention to the geographical location of the author. I think that's why I settled on Reich's book as my main timing guide. But maybe this quote provides a clue to jbest's problem?
A LOT more links on espalier, but I don't suppose you want to wade through all that. I think there are others, but that's all I can think of right now.