Pruning tips for your garden
Winter is prime pruning season for many plants. A good trim keeps them healthy and promotes growth – and can even help increase your stock of plants.
A cut above
One of the best things you can do for your garden this winter is to prune. Not all plants need it but, as a general rule, deciduous trees and shrubs – like roses, hydrangeas and some stone- and fruit trees – will benefit from a good trim. Knowing where and what to prune is important, especially as this can impact next season’s harvest or blooms. Here are some tips to help you make the cut.
Pruning during winter will help to keep plants at a manageable size, improve their overall health and encourage growth around spring. It helps fruit trees to open up, which allows more air and sunlight into the centre, which is better for your future harvest. As stems are leafless, it is easier to spot and remove dead or diseased stems and branches.
You can also do the same for evergreen trees and shrubs, especially hedges. Look for deadwood (usually grey) and any branches growing inwards. Don’t just remove outer growth, look at the centre of the plant too, towards the main trunk. If this area is neglected, over time it will become straggly and sparse – not a good look.
Timing is everything
It may be tempting to just go for it, but waiting for the right time to prune is important. Trimming roses or evergreen shrubs too early can encourage a flush of new growth, which can be easily damaged with a frost.
For deciduous plants, wait until the stems are leafless. With evergreen trees and shrubs, be patient until the chance of the last frost has passed. In areas with no frost, mid-winter is generally a good time. An exception to winter pruning is the climbing rose – don’t prune in winter as you’ll be removing spring flowers. Only cut back once the flowers have finished, in spring or early summer.
Making the cut
Pruning the right spot is key for healthy growth. It's important to prune stems to just above an outward-facing bud to encourage new stems to grow outwards, instead of towards the centre of the plant.
After pruning roses and stone fruit trees, spray with a solution of Yates Lime Sulfur; this will help control common pests and fungal problems.
Tools of the trade
Not all pruning tools are created equal. “Secateurs are perfect for pruning roses, deadheading and general use,” says Julien Laurent of Fiskars. “Ensure they are sharp and clean so you get accurate cuts and avoid diseases.”
Use shears to prune hedges. For large branches, look for a pruning saw or a lopper, which has longer handles and gears to help with leverage.
Sterilise secateurs after pruning each plant – and after each cut if wood is diseased – with diluted bleach, a few drops of tea-tree oil or disinfectant wipes, to help prevent the spread of diseases.
Prune large branches (more than 10cm diameter) in stages, using the pruning saw on the underside first and then from the top. Repeat until the cuts meet.
Improve the soil and plant health by feeding with an organic-based fertiliser after pruning.
Use pruned stems from plants like hydrangeas and roses to make more plants. Take cuttings that are three to four nodes long, dip in a rooting hormone, plant in propagating mix and place in a warm, protected spot.
How to prune a rose
Step 1: When pruning roses, shape and structure are important. The bushes can safely be cut back by about two thirds and should be pruned so they’ll grow well and look great in bloom. First, stand back from the rose bush and look for dead flowers, branches that cross over one another, branches that congest the centre of the plant and deadwood. These all need taking care of during pruning.
Step 2: Use a pruning saw to remove any dead branches, very old brown or grey wood or thick stems. Always cut on an angle so any water runs off.
Step 3: Use secateurs to remove any lingering flowers and leaves, plus any suckers and growth from the root system below the graft. Select three or five green and healthy branches as the framework for next season’s growth. Cut off unwanted stems just above an outward-facing bud to encourage growth away from the plant’s centre. Again, cut on an angle.
Step 4: Apply pea straw mulch around the rose to help the plant retain moisture as the weather warms up. Don’t put the mulch too close to the trunk of the plant, as this might cause rot or mould. After you’ve applied the mulch, water it in. You can also apply rose fertiliser to an advanced rose bush but, if it’s a new one, wait until it has become established.
Tip: After hydrangeas finish flowering, prune back by up to two-thirds – they’ll reward you by flourishing in spring!
Learn how to trim trees to keep them strong and shapely, avoid damage and allow for new growth: bunnings.co.nz/howtoprunetrees. For all your pruning products, head into your local Bunnings store to pick up your tools.
Photo credit: Brigid Arnott