Of all the skills associated with the gardening arts nothing has come close to acquiring the same degree of mysticism and superstitious dread as pruning.
A great deal has been written on the subject; and a great many television gurus have gambled their reputations on being able to lead the gardening public through the labyrinth of pruning lore... losing many of them along the way of course.
The simple fact of the matter is that pruning is only as complicated as you care to let it be. Those with a taste for it could devote a lot of time and energy to mastering the finer points of the art, keeping mental stock of the precise timing for specific pruning operations, and fretting about the idiosyncrasies of each and every plant in the garden. But you don't absolutely have to, just as you don't absolutely have to wax your car every weekend. Leave that to the obsessive-compulsives in your neighbourhood and relax. Basic pruning is easy!
The first rule of pruning - the Golden Rule - is, if there isn't a good reason to prune that you completely understand, don't do it.
Good reasons to prune are:
The Pyracantha in the front garden rips your kilt off whenever you walk by with the groceries.
A lot of your Philadelphus is dead, dying, or embarrassingly ugly.
You can't see out of the front windows anymore.
There are, of course, other good reasons that will come up from time to time. But the point is, unless one does, there is no need to bother doing any pruning. Pruning is a chore for you; but, for the plants in your garden, it is surgery: Don't perform unnecessary surgery! Your plants can't sue you, but they can take all your spare time in compensation for the abuse they have suffered.
If you're even slightly serious about gardening, especially when it comes to pruning, invest in some good quality tools. These will not only last a lifetime (in most cases), but reduce the grim business of work in the garden to something that closely approximates a pleasure. So much so, in fact, that many have been known to take up gardening as a hobby.
The key to preserving the pleasure of owning good quality tools lies in keeping them in good working order. This means keeping sharp the things that are meant to be sharp, and keeping everything else clean, lubricated, and adjusted. This is especially important for pruning, in order to produce wounds that heal quickly (surgery, remember?) and reduce the spread of disease.
To most old gardeners the daily snips of the gardening day, the 'fine tuning pruning', were the work of a sharp knife and a deft wrist. Much of this work has been taken over in the modern garden by gardeners of weaker metal with secateurs of far superior metal, design, and precision.
Pruning knives generally have a heavy blade, which curves towards the palm near the tip. This time-honoured design allows for quick, clean cuts with a practised flick of the wrist.
Secateurs are often called pruning shears. There are two types, roll cut and anvil. Roll cut secateurs are preferable, because the curved blade produces clean, precise cuts, with a minimum of bruising. Anvil type secateurs have a straight blade which cuts against a flat surface. Some operate on a ratchet principle, which magnifies the grip strength of puny gardeners. But the bruised stumps they leave behind take longer to heal and invite disease.
Loppers are the next level of progression in the pruning arms race. They are basically big secateurs with long handles. Like secateurs, the best are the ones with a roll-cut action. They are usually recommended for pruning anything larger in diameter than a finger.
Loppers are also useful for pruning small shrubs, because they allow a gardener to work standing up, and at a reduced risk of being poked in the eye.
There is a wide variety of pruning saw designs. Bow saws have a curved frame into which a flexible blade attaches, like the string of a bow. They resemble big hacksaws. Other types feature blades which fold into the handle, like big pen knives. Naturally, they come in all shapes and sizes, and vary in quality.
For most garden pruning jobs the ideal choice is a saw with a wooden pistol-grip handle and a curved blade 13-15 inches long. It should have six or seven triangular teeth per inch, for a fine cut. And the teeth should be off-set, so that the cut is slightly wider than the blade, to reduce binding.
The unfortunate side effect of cutting away unwanted branches is that you also cut away potential flowers, which most gardeners want. The preferred time to prune for maximum flower production is after the flower show is over for the year. Spring blooming plants, such as Forsythia, can be dealt with in this way, because there is ample time to produce new growth, which will mature before the onset of Winter. The danger in pruning Summer-flowering shrubs late in the growing season is that the new growth, stimulated by pruning, may not have time to 'harden off' (a process called lignification) and may be killed by frost.
The sensible gardener will have realised that, where x equals the number of branches on a shrub in need of pruning, x minus three or four isn't going to make an appreciable difference to the flower show anyway. This insight allows the gardener to prune in late Winter or early Spring, while the plant is dormant. The advantage of pruning during dormancy is that there are no leaves to get in your way; so it is much easier to judge how best to improve a plant's form... or how least to ruin it.
The first task in any pruning assignment is to take care of the three D's: dead, diseased, or damaged wood. Diseased branches should be burned, so that there is no danger of pathogens finding their way back into the garden. Pruning tools that have been used to removed diseased plant parts should be cleaned thoroughly with a chlorine solution or a commercial disinfectant.
The next objective is to get rid of any crossing branches, and remove anything that clutters the centre of the plant. How aggressively you attack this problem depends on the type of shrub and how naturalistic you want your garden to look. The idea is to create a nice open form, with lots of air movement and space for new growth. It is much better to take away three to five of the oldest stems each year than it is to go mad and then give the shrub ten years to relearn bad habits.
The challenge of pruning evergreens can be a bit daunting. In general, they tend to have forms which amplify mistakes and take forever to grow over, chastising you for years with silent reminders of your pruning ineptitude. Many evergreens are reluctant to produce new basal growth, which means you will have to live with any serious maiming you cause.
Pruning spreading junipers can be unnerving, because a bad decision can result in a gaping hole, revealing all sorts of dead twigs and ugliness. With a little practise, however, junipers can be handled with confidence. And a well-pruned juniper is something to feel proud of. The secret is to take the time to understand the relationship of each branch to the rest of the shrub, to know which bit covers what. Then slide your secateurs or loppers in horizontally, and make angled cuts, so that the the wound is hidden by the overhanging branches left behind. If you're careful, you can control the shape of your junipers, without leaving any visible wounds. The test of your skill should be how little evidence there is to be seen.
Dwarf pines, such as Mugo pines, are usually pruned by pinching back the new growth each Spring. This is called candling... because of the resemblance the new growth bears to candles. It is dificult to reduce the size of an old pine without ruining its form.
Yews are easy. They will forgive you for the worst blunders imaginable, because they have the ability to break dormant buds from even the oldest wood. This means that you can chop a yew back savagely, and new growth will soon appear. Chopping a venerable old yew is something one should only do as a last resort though.
Once again, the first thing to look after are the three D's. Then you should inspect the inside of the crown, to see how much clutter needs to be removed. The objective is to thin out the interior to allow air movement, without creating any gaping holes in the tree's appearance from the outside. This means making a judgement about which of the scaffold branches need to be left to give the tree its shape. Anything that interfers with these should be removed. Water sprouts, or suckers, are vigorous lateral branches thrown up by trees with too much energy. They should be removed, because they will soon spoil the tree's form if left unchecked.
Large branches should be removed using the three-cut method:
The first cut is made in the underside of the branch, about two feet from the trunk. This cut should be no more than one third of the branche's diameter. If you cut any deeper, there is a good chance that your saw will bind in the cut which can be very embarrassing.
The second cut is made on the top of the branch, two or three inches from the first. This cut should sink until the branch snaps and falls to the ground. If this cut is made farther from the trunk than the first cut, it is called a 'drop cut'. If it is closer to the trunk, it is called a 'spring cut', because the branch will tend to jump out slightly.
The third cut is the 'flush cut'. It is a single cut, made through the swollen base of the branch, so that all that remains is a smooth surface.
Wound dressings are seldom necessary. They can, in fact, actually inhibit the healing process if they are improperly applied. It is much better to leave a nice clean surface, with no loose or torn bark. One of the most satisying aspects of pruning is to watch a clean cut form a callous and gradually heal over. After a few years, it should be difficult to see where the cut was made.
The essence of good pruning is that it goes unnoticed by the casual observer.