Pruning is one of those gardening tasks that mystifies a lot of people. I’m commonly asked when and how it should be done, and have found that some female gardeners are reluctant to get stuck in and have a go. Blokes though, seem to show little hesitancy, or restraint.
I have very clear memories from childhood watching my Dad, who wasn’t really the gardener in the family but a demon with the hedging shears, hack in to all manner of plants with reckless abandon, only to have Mum, the head gardener, chastise him for being overly enthusiastic. Conifers in particular seemed to get singled out for special attention, and within the space of an hour, I witnessed a couple of healthy plants reduced to a neat but bleak structure of old dead wood. Rule number one of pruning conifers: don’t prune into old dead wood.
Why do we prune? The most basic answer is that we prune to shape a plant. Of course this suggests a secondary question: why do we shape plants. Now we’re getting into the real nuts and bolts of the issue, and there are multiple reasons for why a gardener might want to take up a pair of secateurs and start hacking away at what would otherwise be perfectly healthy vegetation.
Plants are shaped to keep excessive growth in check, to control pests and disease, and to train to a certain form. Sometimes plants are shaped to become living sculptures. In the case of fruit trees however, the primary reason we prune is to produce bumper crops. This seems counterintuitive, since almost all productive trees will bear fruit regardless of whether they are pruned or not, as long as their pollination needs are met.
But my garden, for example, is designed to feed my family. I want the highest yields possible from a couple of acres, and to achieve this, I need to grow trees that are trained to produce fruiting buds rather than excessive vegetative growth. So let’s cut to the case. Summer pruning of deciduous fruit trees is largely about controlling a tree’s vigour, but winter pruning is formative – it’s all about creating a productive, long term framework of branches.
In the small home orchard most deciduous varieties, including apples, pears, peaches, apricots plums and cherries are best trained to a traditional open vase or goblet shape. This tree form allows good air circulation, which helps control fungal disease, makes for easy netting and picking, and avoids uneven fruit ripening. In basic terms it involves taking out a tree’s central leader, selecting a framework of about four main branches symmetrically spaced around the trunk, and the removal of any growth crowding the centre of the tree. An old rule of thumb is that a pigeon (or the gardener’s hat) should be able to fly unhindered through the middle of the tree.
Of course there are different techniques for different varieties. I’ll get into the specifics of these in next week’s article, but for now, concentrate on forming a good solid framework. For established trees, it you should also prune off any branches that are dead, diseased or worn out.
When making your cuts always wipe the blades of your tool with metho or a bleach solution preferably between each cut, but at a minimum when moving from one plant to another. This helps curtail the spread of disease. Some orchardists still like to apply a wound mastic or sealing wax to the cuts in order to avoid infection, but this isn’t necessary and can actually hinder a tree’s natural healing abilities.
A far better way of preventing disease is by making clean pruning cuts. Invest in good quality gear, and keep it sharp. I’d be lost without my Felco 2 secateurs. This classic is made to the same specifications as when it was first released in 1948 and is a pleasure to use, but other companies make comparable tools. I also use a pruning saw made by US company Barnel, a bow saw for larger branches and a heavy duty pair of loppers. Both the secateurs and loppers are regularly sharpened with a hand held diamond sharpener. Sharp tools are safer for the gardener and better for your plants.
Next week – specific pruning techniques for various fruiting plants.
First published in The Chronicle, 25th July 2009.
