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[Alan Haigh <alandhaigh@gmail.com>]

Thanks Lee.  I just read a bit about summer pruning from a David Ferree book on-line and he seems to be saying not that summer pruning is not more dwarfing than winter pruning, but that it is not a practical way of controlling size due to reduced yield, fruit size or soluble solids when performed aggressively enough to reduce vigor. 

 

The research he sites (as I understand it) only suggests that the removal of annual wood in summer doesn't reduce vigor- what he refers to as "moderate pruning".  This is not the kind of big branch removal that goes on when I'm doing structural pruning of huge apple trees.

 

He warns against summer pruning of inadequately vigorous trees because "the loss of leaf surface and photosynthate capability it represents can only aggravate a pre-existing vigor problem".   This indicates that he considers summer pruning to be potentially more dwarfing than winter pruning.

 

It is interesting to note that Dave Wilson nursery advocates growing 4 fruit trees in a space usually used for 1 and to maintain the trees by vigorous repetitive summer pruning.

 

I have long been suspicious that such a practice would lead to watery fruit without much sugar, but the practitioners of this method swear by it.  I have never read of anyone attempting this method complaining about the poor quality of their fruit.  They tend to have an almost cult-like enthusiasm for their method. 

 

These advocates are all using summer pruning to control vigor of their trees.  It might not be a practical means of commercial fruit production, but that is not what most of us are doing.

 

I am not at all frustrated by people making anecdotal observations that might not be factually based- as long as they understand the limitations of that kind of information.   It's also important to know the limitations of research geared to commercial production when applied to home growing.

 

My summer pruning may reduce the yields of the trees I prune significantly, but my customers still get much more fruit than they could ever use.  The size and quality of apples are not noticeably affected.

 

There may be other research that supports the blanket statement that "summer pruning is not more dwarfing than winter pruning" and I would be very interested to see it.