If you imagine that pruning is one of gardening’s dark arts then you are not alone. Many gardeners feel the same about it. Whilst it’s true that pruning can be an involved and complicated subject, in most cases it’s straightforward. Even when there’s a bit of knowledge and skill required, it’s not a job to be frightened of. Once you know how, you’ll find pruning enjoyable, satisfying, even cathartic. The problem is knowing when to stop!
Whatever you do, don’t become what I call a ‘chopper’. These are people who go about pruning indiscriminately without any consideration for the impact they are having on a plant. Choppers are often motivated by a desire to cut things back in order to regain control over a plant or garden that’s been left to its own devices for too long. Even if you are clearing an abandoned plot or overgrown shrubbery, there are ways to do it that are better for you and any plants you wish to save.
In their natural habitats plants are rarely pruned, unless you count the actions of extreme weather, fire and foraging animals. You might think that it would follow that there is no need to prune your plants at all, and technically there isn’t. However, most plants in a garden environment will benefit from some kind of pruning at certain points in their lifecycle.
Pruning at a glance
- Each type of plant needs pruning slightly differently, so be sure to know what you’re pruning before you start. If in doubt, leave well alone.
- Check you have the right pruning tools and make sure they’re clean and sharp before starting - a good pair of secateurs will be your greatest friend.
- Assess whether you need help with the job and make sure you are able to work safely. Wear gauntlet gloves and goggles for protection.
- Enjoy the pruning process - it should be satisfying for you and transformative for the plant.
- Water and feed plants after pruning, especially if you have removed a lot of growth.
These are the main reasons why we prune:
- To improve the health and vitality of our plants - many plants have a tendency to become tall and untidy if they are allowed to grow unhindered. As they become taller and older they also start to grow more slowly. In turn the production of flowers and fruit might decrease - we see this happen in old apple orchards and vineyards for example. Plants generally respond to pruning by producing vigorous new growth, brighter flowers, larger leaves and more abundant fruits and seeds: pruning effectively gives them a new lease of life. As a general rule, light pruning, as you might give a hedge or topiary bush, will produce a modest flush of healthy new growth. Hard pruning, for example cutting a shrub down to a few centimetres above ground, will often produce vigorous regrowth, occasionally resulting in a bigger plant than you started with. Hazel and buddleja (butterfly bush) are two plants that respond especially well to regular hard pruning. But, here’s the rub, not all plants cope well with pruning. You must find out what you are tackling before picking up your secateurs or shears. Appropriate pruning will keep a plant happier and healthier than it would be if left unattended, and may well prolong its life.
- To create a pleasing shape - a great deal of pruning is carried out purely for cosmetic reasons. Topiary, bonsai, hedges, standard roses, espalier fruit trees and pleached limes are all trimmed and pruned to create neat, interesting or architectural shapes. They will quickly revert to wilder forms if left untended for any length of time. Humans have pruned for aesthetics for centuries, often using this as a demonstration of their mastery over nature. Make no mistake, nature will always triumph. If you prune for beauty, be prepared to keep at it for as long as you want your plant to stay in shape. It’s also worth noting that many plants, Japanese maples and conifers for instance, produce the most beautiful forms without any serious intervention. Sometimes it’s best to leave plants well alone.
- To keep plants within bounds or influence their direction of growth - the best advice is to choose plants that will not outgrow the space you have allotted them. Whilst sound advice, there is not a gardener alive who has not planted something that’s grown too large, or inherited a garden where the previous owners gave little consideration to the ultimate size of their plantings. Much of the pruning we undertake in our gardens is to keep plants under control and out of our way. Sometimes we want a plant to grow in a particular direction, for example when training a wisteria across the front of a house. Here, judicious pruning will ensure the climber goes where we want it, and not under the eaves or into a neighbours’ garden. If you become saddled with a plant that’s never going to remain within bounds without regular attention, it’s worth considering whether it would be better to remove it rather than tolerating its butchered form for years to come. Even in the largest and most prestigious gardens, plants are often removed and replaced once they cease to be attractive and manageable.
In practice, good pruning will address two or three of these purposes at once. For example, trimming a young lavender bush to 20/25cm above ground after flowering will first of all prevent the plant from becoming tall and woody. Tall, woody lavender bushes can be unsightly, vulnerable to wind damage and hard to prune at a later date. A well-trimmed bush will look neater, live longer and produce stronger foliage and flowers year after year. Good pruning will save you money since you can rejuvenate a plant rather than replace it.
Before pruning any plant it’s important to know exactly what it is. If you are not certain, there are thousands of gardeners, hundreds of books and tens of plant identification apps that can help you make a positive ID.
Every plant has its own pruning requirements. Even within a plant genus such as clematis, rose or apple there will be different advice depending on the species, variety and what you are trying to achieve. Don’t be put off, as once you know what you’re working with, the actual pruning should be pretty easy.
Having established what plant you are pruning, carefully assess whether you are equipped and able to tackle the job yourself, or whether you need help. Basic pruning equipment is listed below. In practice many gardeners get by with a couple of pairs of good quality secateurs, a pruning saw, shears, loppers and a ladder. With this kit you are equipped to do most routine pruning work.
Only you can judge whether you are fit and dextrous enough to embark on the task in hand. Remember that good pruning tools will be very sharp, and that branches can flail about in the process of pruning. Always watch what you are doing and know where your blades are in relation to your fingers. Protect your eyes with goggles and your hands with gloves when tackling anything other than the simplest trim. Larger boughs can be extremely heavy, particularly when they are in leaf. If flexed they have a tendency to ping back at you. When using a ladder, have someone with you to hold the bottom and do not overstretch. It’s far safer to come down and reposition yourself if you can’t reach the area you want to prune. Be aware if you’re tackling a plant with thorns, spines or irritant sap. A good pair of supple, gauntlet-style gloves will protect your hands and wrists in most instances.
If the job feels like it’s too much for you, it probably is. Trust your instincts. Enlist the help of a gardening friend if it’s a two person job. Removal of large branches and the felling of entire trees are usually jobs best left to the professionals.
Finally, it’s wise to consider what you will do with the resultant prunings before starting a job. Small amounts of soft hedge clippings and twigs no wider than your little finger can be chopped up or shredded and added to your compost heap. Anything larger, bulkier or drier may need to be taken away and composted elsewhere. Large branches and logs can be stacked up in wild parts of the garden to provide shelter for animals. Any material that you believe might be diseased or treated with chemicals should be burned and not composted.
Importantly, do not wade in and hope for the best. Do your research and get prepared so that you can enjoy the process of pruning with nothing to fear.
Basic pruning advice
No article of this length can aspire to tell you everything you need to know about pruning, but here are a few top tips that apply in all cases.
- Always use the right tools for the job. Make sure secateurs, loppers and shears are clean and sharp to make pruning as easy as possible. If you or the blades are straining, it’s likely you’ll be doing yourself, your tools or the plant a damage.
- There is generally a best time to prune or trim any plant. Finding out when that is will save you time and trouble in the long run. (pruning calendar to follow at a later date?)
- Every cut should be cleanly made so that the plant is not bruised, torn or grazed in the process. Rough surfaces provide a haven for diseases and look unsightly.
- Always cut just above a leaf joint, close to a bud, at the fork on a branch or just beyond a branch collar (the swelling where a branch joins a main stem or trunk). This ensures that the plant’s energy is channeled upwards towards an alternative growth point and not a dead end. Long portions of stem with no buds will generally die back to the bud below, leaving a section of dead wood.
- If you are removing a large portion of a plant, be aware that you are significantly reducing its capacity to photosynthesise and therefore feed itself in the short term. The more of the plant you remove and the more frequently you do it, the more you will weaken it. Feed and water a heavily pruned plant until its re-established. Think of it as nursing your plant back to health after a major operation.
- Always cut at an angle so that water or sap cannot stagnate on the cut surface. If the wound is not able to dry out then fungal infections may take hold and damage the plant. Some plants may bleed sap for a little while after cutting. Pruning at the correct time of year will keep this to a minimum.
- You are generally safe to remove any dead, diseased, weak or damaged tissue at any time. If you are not sure if a woody stem is alive or not, scratch the surface with your thumb nail. If the tissue beneath is green, it’s alive. If it’s brown or grey, it may well be dead.
- If any branches cross one another, remove one or both of them. Branches rubbing together can create open wounds that encourage diseases. As a rule you want the centre of any bush or tree to be open and free of crossing branches.
- If you are cutting a plant back to a level where there are no visible leaves or shoots, be very sure that the plant will rejuvenate itself from there. Several plants, including most conifers, will not reshoot from ‘old wood’. If you proceed, you may be left with an unsightly stump or a completely dead plant.
If any of this sounds daunting, remember that trimming off the odd stem, bough or branch here and there is unlikely to do a plant much harm. Sometimes needs must. It’s your garden and you call the shots.
Tools and Equipment
Secateurs are one of the most useful gardening tools and most gardeners will have at least one pair. Buy the very best secateurs you can afford as they will last longer and make pruning work easier. If you can afford a second or third pair, then choose one for light work, another for tougher jobs and perhaps keep a pair in reserve. Secateurs make a great gift for any gardener - you can’t really go wrong.
There are two types of cutting action: ‘bypass’ and ‘anvil’. Bypass secateurs have a single-edged blade that slices past a thicker base as it cuts, just like a pair of scissors. This is the most precise and effective action for most pruning jobs. Anvil secateurs have an upper blade that slices down onto a flat lower base (the anvil) like a knife on a chopping board. Anvil secateurs are less precise and clean-cutting but can take higher force. These are best reserved for pruning dead wood and harder material.
Secateurs can be used to cut most ‘soft’ (non woody) growth and woody stems up to 1cm in diameter. If the blades don’t slice easily through the wood, then they may need sharpening or the job may need a more robust tool, such as a pair of loppers. Don’t tug or wrestle with thicker stems and branches as this will damage the plant, the blades and potentially your wrist, arm or shoulder. Never cut metal, including wire, with secateurs. Avoid dropping them if humanly possible. Both actions can damage blades irreparably.
Loppers take over where secateurs are no longer up to the job. They should be used for cutting branches with a diameter between 1cm and 3cm, after which you need to deploy a pruning saw. Loppers are brilliant for heavier pruning because they have long handles which offer extra leverage. Using a good pair of loppers can be very satisfying. Again, loppers are available with anvil and bypass cutting actions.
Pruning saws are small, curved saws with relatively deep teeth that are designed for cutting ‘green’ wood. This prevents them from clogging up with sap and gunge when used. A pruning saw can be used for cutting through branches 2cm-10cm in diameter provided they’re not too hard.
Shears are the perfect tool for trimming box, lavender, heathers, thyme, yew and all forms of topiary. They are designed for clipping fine stems and should never be used in place of secateurs. Shears should slice effortlessly through the stems making the job easy and enjoyable. If they don’t, the blades may need sharpening or the stems may be too thick for shears. It takes a degree of skill to use shears well. Don’t worry if you make a few wonky cuts to begin with. Plants are more tolerant than many people imagine and will soon grow back.
Snips should only be considered a pruning tool for very fine work such as maintaining bonsai. Otherwise they are best suited to trimming herbs, cutting string, picking flowers etc.
A professional might clean and sharpen their cutting tools daily. The average gardener probably needs to service theirs weekly or monthly, depending on how regularly they are used. Cleaning removes sap and other grime that can gunge up the blades and springs, preventing them from opening and closing smoothly. Sharpening ensures the blades cut cleanly and with minimal effort.
After every use, clean and dry your tools thoroughly. Never put them away wet. A wipe with a cloth soaked in camellia oil or WD40 will keep blades rust free. If you have been pruning plants that you suspect may be diseased, disinfect the blades with a dilute disinfectant before moving on to the next job. This is especially important with sap-borne diseases such as mosaic virus.
10 point pruning checklist
- Identify your plant.
- Research the best time of year to prune.
- Identify the most appropriate pruning method for what you’re trying to achieve.
- Check you have the right tools and make sure they’re sharp.
- Assess whether you need any help with the job.
- Make sure you can work safely.
- Enjoy the pruning process - it should be satisfying for you and transformative for the plant.
- Dispose of your prunings appropriately.
- Clean and dry your tools before retiring for the day.
- Water and feed your plant afterwards if you have removed a lot of growth.