The heading is misleading, because the real apple beasts are varieties that push out too much upright wood and encourage excessive winter pruning which can create a vicious cycle of excessive vegetation- but it was too close to furry beasts to resist.
I’m writing here about pruning free standing apple trees on vigorous rootstocks, where the lion’s share of my experience lies. It also strongly applies to pears- Asian and European, both of which can succumb to spurring up to the point of inadequate vegetative growth. I’ve also used this approach with apple trees on M26, grown without irrigation in thin soils, which will often runt out in these conditions, no matter the variety.
What a fruit grower strives for is moderate growth and moderate growth relies on a certain amount of upright vegetative shoots being retained on trees every season. Often these shoots are the sources of the trees best fruit on their (the shoots) second or even third year, with flower blossoms forming on the oldest part of 2 or 3 year old wood. These shoots also serve the growing fruit nearby and send some energy to serve the wood and roots below.
The other day I was pruning a Braeburn apple standing next to a Northern Spy. The trees are in about their 13th leaf, growing in sod in a rich, somewhat excessively wet (because of sand subsoil) clay loam. Even with the competing sod, the trees tend to grow very vigorously here once established- most are on 111 rootstock, as are these two trees. These two varieties have opposite growth habits- Braeburn lives to grow fruit and N. Spy to grow wood- at least when young.
Managing their growth is so different that they may as well be distinct species. I will briefly discuss the N. Spy later but the Braeburn is the spur monster this topic is primarily about. These variety types usually must be pruned to coax more vigor, which means cutting back wood to vigorous upright shoots whenever possible and removing lots of small, hanging wood (which often produces small, low quality fruit and saps energy from the tree). Branches weighted down in the previous season by crop to below horizontal, especially in the lower first tier of scaffolds, need to be pruned back to a vigorous upright, even if it means cutting the branch back further than you would otherwise want.
When a spur monster succumbs to excessive spurring that leads to inadequate production of fresh growth, which can happen on stressed (too much crop of not enough water) young apple trees or declining aged ones and often occurs with pears, especially Asians, you have to remove a lot of the knobby spur growth and as much wood growing below horizontal as you feel safe to do. Supplementary N. and irrigation may be helpful, and removing all flower buds for a season. Asian pears routinely produce excessive spur wood and way too much fruit, so I routinely remove a percentage of spur wood from them, even as they are growing well. Sometimes pears only produce a few excessively vigorous shoots and little moderately vigorous ones. This is the one case where I will stub cut into annual wood.
As far as the wood monsters such as N. Spy, I find it useful to immediately remove all branches more than a third the diameter of the trunk for the first several years quite helpful. By the fourth year I tape uprights coming off the scaffolds to temporary scaffolds, bending them to near horizontal. Second and third tier wood I will often tape or otherwise pull down to a weep. Scoring also helps, especially to calm down the top of the tree, where you use a sharp pruning saw just above the first tier, cutting through cambium into the surface of sapwood. I cut half way around and go up a few inches to do the other side of the trunk. This is best done around bloom. Sometimes I cut vigorous uprights back to 2 year wood, especially if there are flower buds on them. Stub cuts back to older wood is not vegetatively stimulating in the way cutting into 1-year wood is.
Michael has posted that he gets great results from his espaliers on vigorous rootstocks by cutting back new shoots a few times during the summer, immediately transferring them into fruiting wood. Sometime I would like to try this on a vigorous free standing tree, where it is bound to work as well, although I’ve only heard of the method being used on espaliers.
