Importance of recycling on tall spindle apple plantings
A key to successful canopy development is to retain and encourage productive growth by recycling vigorous branches in a tall spindle apple planting.
Having ventured into a few tall spindle apple orchards over the last year, I am reminded that I need to remind growers new to these high density systems that a key to canopy development and success is how to retain and encourage productive growth.
One mistake I continue to see are trees in which too many branches are being retained in the canopy, which compete with vertical development of leaders in trees aged 2-4. Just because you purchased trees with a lot of “feathers” does not mean you can retain them all. Too many will stymy leader development. If this happens, canopy volume suffers and so does yield on a per acre basis. Unfortunately, once trees get into this state, it is difficult to reverse the trend.
Once trees get into their fifth and sixth growing season, recycling vigorous branches is very important. Generally, the recommended protocol is to prune or remove those branches where caliper is 50 percent or larger compared to the leader from which it grows. In particular, remove those that have an upright trajectory (see thick dash mark in image). They will usually remain vigorous and vegetative. Instead, retain branches that are weak and possess spurs, meaning they are more “reproductive” (see image).
Michigan State University Extension recommends growers prune or remove two to three branches per tree. Leave a stub of 3-4 inches. When making the pruning cut, make it so that the cut is oblique with the cut surface facing upward. We call these “bevel” or “Dutch” cuts (see YouTube video on pruning tall spindle apple branches). Pruning in this manner will discourage adventitious shoots from forcing on the upward side of the branch. During the growing season, follow-up with training adventitious shoots downward (below horizontal) to slow their growth and encourage flower bud induction in mid-June to mid-July.
Spend time during mid-June to mid-July bending branches down using elastic bands and it will reward you many times over in subsequent seasons with productive trees.
For more information, see the YouTube video “Pruning Tall Spindle Apples: Recycling Strong Branches.”
Thanks to Denise Ruwersma, research assistant, for working on the SSCD project for videography and plot canopy management.