A note on Apple Pruning
Spring blossom on espailer trained and step over apples at RHS Rosemoor
When I started out in Horticulture pruning was one of those things that seemed not only a bit daunting (working with people who were seemingly confident experts in the field) but just very ambiguous, confusing and also quite tedious. Sometimes the later still holds true, especially whilst pruning at the coldest time of year; everything becomes a bit numb after a while, and combined with the post-Christmas slump, pruning overgrown apple trees doesn’t always feel naturally intuitive or very much fun for that matter. But conversely this is the reason it can be so rewarding, because it requires thought, understanding as well as sensitivity to the trees. And most importantly good pruning practice will help to reap a healthy crop of fruit later on.
I often have seen fruit trees hacked about with a gung-ho, ‘can do’ attitude that not only inhibits the tree’s ability to fruit but also encourages it to respond with enormous vigour, one could imagine in protest. Water shoots fly out in every direction bearing only vegetative growth and energy is simply directed into responsive growth as opposed to happy healthy fruiting.
So I thought I’ll outline below a few principles and pointers for winter fruit pruning to help demystify and simplify the process. Some of these principles can be applied more generally to pruning.
Canker wound on apple tree branch
Prune out the obvious first- namely anything that’s Dead, Diseased or Dying- the 3 D’s!! If you do any sort of horticultural course then this will be drummed into your mind like a mantra at some point inevitably. Look for any branches that may be broken, snapped or damaged. Look out for signs of canker or rubbing; sometimes two stems rub against each other wounding the cambium layer or they may be rubbing against something inorganic such as supporting wires. This type of wound won’t necessarily need to be pruned out but it is helpful to get rid of the source of friction by retying the stems or cutting out one of the rubbing branches. In terms of disease, canker is common in apples but also look out for congealed sap on the outside of the stem or fungal bodies which may be a sign of underlying issues.
Never prune stone fruits in winter! All stone fruits – your plums, damsons, peaches apricots should only ever be pruned when they are in growth and their sap is flowing. They are more prone to bacterial canker and silver leaf; by pruning when in growth the wound bleeds and helps to keep it clean. Prune once they begin to leaf up and stop pruning in late summer- early autumn.
Winter pruning stimulates growth. This one is a bit of a paradox but it is true; winter pruning will stimulate growth whilst summer pruning is restrictive. That is why only a third of the tree’s growth should be pruned out at one time and more serious renovation should be undertaken over several years. Otherwise, the likelihood is that you will end up trying to contend with a huge flush of vigorous unfruitful vegetative growth, particularly water shoots in response to heavy pruning. Trained fruit trees such as apple and pear cordons, step overs and espaliers are typically pruned at the end of summer or early autumn when the sap has slowed down sufficiently to prevent vigorous regrowth but enables the tree to be pruned to a tight framework, this also helps to improve ventilation and lets more light in to help ripen the fruit later in the season.
Make fewer more substantial cuts rather than lots of little cuts if you are renovating a congested tree. Rather than snipping at all the side shoots focus on removing larger branches that might be growing inwards or creating congestion working towards creating a more open goblet shaped framework, improving air movement and light levels within the tree and if necessary, consider reducing the height to make the fruit more accessible.
Be sure to use good sharp tools and make clean cuts; this might sound obvious but ragged cuts that tear the wood are more vulnerable to disease. A good cut sloping away from buds and one that doesn’t leave a stump behind prevents the build-up of moisture and should heal more quickly. Wound paint is no longer really rated but sharp tools fit for purpose and making good cuts is really important, as is sterilising tools between trees and after pruning out infected wood. I use a solution of Jeye’s fluid but there are all sorts of sanitising solution available.
Evidence of tree tie wearing down away cambium layer
Check Tree Ties this is something that often gets overlooked but after a couple of years as trees put on growth tree ties can become too tight and start to erode the cambium layer which creates an opportunity for disease. Winter pruning is the perfect time to check that tree ties haven’t started strangling their hosts and to adjust as necessary.