I have a 4 to 5-year old Tompkins King apple on an M26 rootstock. Unfortunately it got away on me and there is a long stretch on the trunk between the bottom circle of branches and the top. The trunk is about 3/4" in circumference. Would there be a negative consequence for pruning the top half off, to promote some additional side branch growth? Oh, and it just got planted in the ground yesterday.
Short answer is no. You'll be removing the present leader and creating an "open centre" tree (a search for the term will yield lots of information). It's a common way to shape apple trees, so no particular worries. You might want to prune out some of the remaining side branches if they're particularly crowded as you'll want to select a few well spaced and positioned ones to become scaffold limbs, and may need to adjust their angle (often done via twine and pegs) for the first couple of seasons if they're growing too vertically.
Thank you! Do you think that if I were to make little horizontal cuts on the trunk above some buds, that it might stimulate branch growth?
Yes, notching like this can stimulate branching--if needed. Look up "notching apple trees" for specific instructions. There's often enough branches at the point you remove the leader, however, so stimulating additional branching is unnecessary. Can't say in your case without a photo, though.
Hi Woodschmoe, I think I've successfully uploaded a pic. So, looks like the tree was nipped at 40" originally which gave it the bottom 3 branches. Then there's another 33" of unbranched trunk, then there are some branches at the top. What do you think?
I'd say either grow it as a modified central leader (it very nearly is already, if you remove the top most leader) and try stimulating (or encouraging any that grow) a bit of branching in the bare mid section, or take it back to the lowest whorl and maintain as an open centre--the three lowest limbs are already in good position for this. If you want some height to it, go with the former. If you want to keep it small and easily picked, the latter.
I would definitely leave the tree alone for a year or may be two. Right now it has enough stress to overcome (transplant shock) and needs to get used to its new environment and get established. I don't think it is a good idea to make it struggle on both ends at once. It could also give you more time to make sure how you would like to shape it.
To do corrective pruning at planting or not is a matter of opinion: orchardists, nurserymen, and the like frequently prune during planting/transplanting with no ill effect--indeed, this specialty apple grower recommends it: http://www.orangepippintrees.com/articles/pruning-a-newly-planted-fruit-tree. Not sure I agree with all of it--for instance, one never does a "one time initial pruning". The first cut is never the last, and the response to pruning tends to lead to the need for ongoing pruning to maintain the desired form, but the take away point remains: corrective pruning at planting is common amongst apple growers. On the flip side, some sources and studies indicate that the tree will require it's energy to produce roots, and too much pruning will re-direct resources from root growth to wound healing. This is sound enough, but the degree to which it matters seems variable, and not all sources agree. In most cases it's acknowledged that doing so to correct the structure of young trees (the case for you) is acceptable, particularly when these are thinning and not heading cuts (what you would be doing). Much of the literature on the topic seems to refer especially to the historic nursery practice of heading back all trees at planting, and is not specifically addressing the initial corrective pruning of fruit trees. Anecdotally, I've planted hundreds of fruit trees, dozens of them apples. I often do initial corrective pruning at planting, and haven't noticed them struggle--ditto for nurserymen, orchardists and growers throughout the ages. It also varies depending on the tree--I planted a number of bare root Frisia locusts a few years back, and those that were left unpruned at planting sat for years with little top growth. Those I headed back at planting are twice the height and diameter of those left unpruned, with much greater vigour. Hopefully this goes some way to explaining the contrary opinions offered. As Sundrop suggests, there's no rush. If you'd rather wait a year, the proffered pruning suggestions won't change: next year you'd still decide between the two forms and prune accordingly.
