Chapter 25 of Bonsai Heresy is about the mistaken notions of avoiding nitrogen in our fall fertilizing by using 0-10-10. The problem it is trying to correct, frost damage from still soft shoots, is more often a mis-timed pruning in the summer.
This is easiest to see in deciduous trees, which may be pruned in late spring / early summer to good effect. That is, good regrowth. The comments in Bonsai Heresy are directed to primarily temperate plants, and in temperate regions June and July are good months to prune back many deciduous trees, which will reflush with new growth.
If, however, strong pruning is done in August, there may be a reflush that is uncomfortably close to the first fall frost. Then you may well get frost damage from that non-hardened growth. And that is totally unrelated to nitrogen.
As Heresy explains in depth, citing several research papers in…
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