Pruning is the removal of plant parts to enhance the health, aesthetic appearance and/or fruiting ability of the plant. Some gardeners may find pruning a little intimidating, but if you start with a basic knowledge of your plant’s natural form, an understanding of the reasons for pruning and the right tools for the job, pruning can be a pleasurable and rewarding gardening task.
Reasons to Prune
- To improve the quality of flowers, fruit, foliage/stems
- To maintain plant health
- To obtain a balance between growth, root growth and flowering
- To restrict growth
- To train the plant
Where to Start
When you’re planning your garden, research the natural forms of the plants you are considering. For example lilacs have a natural V-shape and deodora cedars are the opposite with a weeping form. Pruning these plants into “meatball” shapes is harmful to the plants. Unnecessary pruning can be avoided if you choose plants that are suitable for the site. If a shrub naturally grows to 1.5 m (5’) in diameter, planting it in a 60cm (2’) space is going to result in a maintenance problem. If you inherited a landscaped site, the selections have already been made for you. The next step is to find out how to prune if needed.
When to Prune
Do not prune just because it is spring, different plants have different reactions to pruning and not every plant should be pruned every year. Also when to prune is important because if you prune at the wrong time you can be removing flowers before they get a chance to bloom. To avoid this only prune early spring flowering plants after they bloom. If you are ever in doubt about weather to prune or not, a good guideline is to follow the 3 Ds, prune only branches that are deformed, damaged or diseased. Even better, speak to one of our knowledgeable staff members about the plant in question, they’ll be able to tell you if it will benefit from pruning.
When to prune is a common question. If the plant needs only a light shearing or pruning for shape, it can be done at any time of the year. Take no more than 5-10% of the total volume off.
If your plant needs heavy renovations (such as removing up to a third of the plant mass) it should be done in the spring before the first flush of growth and after the last hard frost. The cuts will soon be covered up by the new spring growth. If the plant is an early spring bloomer you may lose out on some flowers for a year but rest assured your plant will get back on track the next year and be better off in the long run.
Most deciduous plants (those that drop their leaves during winter) can be pruned in the winter when they are dormant. The exception is deciduous shrubs that flower on last year’s wood (usually spring or early-summer flowering plants such as forsythia and spiraea). These should be pruned right after they finish flowering to let the new flush of growth ripen for next year’s blooms. Maples should be pruned when in full leaf mid-June/July.
Evergreens such as rhododendrons, should not be pruned except when used for hedging material (for example English laurel or boxwood). The exception is the 3 Ds and when you have branches crossing and rubbing.
Light pruning at any time of the year is fine for coniferous hedges and plantings, but heavy pruning (with the exception of yews) is not recommended as cedar hedging has a “dead zone” inside the plant. Even if light reaches the area, there are no growth buds to facilitate growth, these evergreens cannot “break buds” on old wood. So, if you prune too hard you will be left with an open unattractive “dead hole” in your hedging.
Roses & Clematis
Refer to our specific care sheets on both roses and clematis to learn more about their special pruning requirements.
The right tools for the right job always makes a gardener’s life easier and safer. The list below will help you choose the tools you need for your garden. Better yet come visit us in store, our staff are happy to assist you find the right tool.
Used for pruning branches that are smaller than 2cm (3/4”) thick. A good pair of pruners are a gardeners best friend so they should always be kept clean and out of the soil (soil granules will dull the blades). Never force a pruner to cut, as in using both hands to squeeze down on the handles. If you need to use force, the branch you are trying to cut is too big and you need to use lopping shears.
This tool is used for shaping hedges and shearing formal shrubs. Select shears that are durable as well as lightweight, since this kind of work takes time and is repetitive. Try extending your arm with shears in hand to estimate the weight, and imagine spending hours with it extended.
These long-handled pruners provide more leverage to cut wood up to 3cm (1.25”) in thickness. The heavy-duty, double action and ratchet types can easily handle wood up to 4.5cm (1.75”).
These are used for pruning heavier branches, 5cm (2”) and larger in thickness. Unlike a carpenter’s saw, a pruning saw cuts on “pull” rather than on “push.” Pruning saws can be purchased in a foldable form for added safety or with a holster to attach to your belt.
How to Prune
Before you make the first cut, always picture in your mind how the plant will look without that particular limb. A good old adage is think twice and cut once, since it’s hard to put the branch back on the plant. When pruning, always prune to either the next growth bud that is facing outwards (away from the centre of the plant) or to the junction where the limb meets the plant. NEVER leave a stub. Stubs are an access point for diseases and infection, but also it looks bad.
Always cut out dead, diseased or damaged materials first (the 3 Ds). Trace the dead branch or limb back to live wood (check by gently scraping the bark to see if the layer underneath is white or light green) then cut just below that point at a growth bud.
Next prune out all crossing branches. Crossing branches will become large limbs that will rub against each other and cause damage to the plant in the future.
Always remember to take time and stand back to check your work, a good look at the plant from a distance can help you to know when to stop. For ornamental deciduous shrubs and trees, the branches should be encouraged to grow outwards. This allows good light penetration and air flow. Prune out branches that tend to grow inwards.
The Safe Way to Remove Large Limbs
If in doubt ask for help from a certified arborist. If the branches you want to remove are a manageable size then follow these directions. First reduce the size of your branch to a manageable and safe level by removing several small pieces with your pruning saw, then make an upward cut halfway through the branch at position A (see diagram below). Trim the branch at position B to remove the branch, and make your final clean cut at position C.