There are a few reasons why home gardeners and horticulturists at Centennial Parklands alike choose to prune most of their roses in winter. Pruning stimulates new growth, giving roses the best chance to put on a stunning flowering display in warmer seasons.
One of the most important aspects of the winter prune is cleaning out dead or diseased leaves and canes from the garden. Diseases such as black spot and die back will have built up over the summer and it is important for new growth to remove this from the surrounding area. We also rake off all old mulch, fallen leaves and weeds which can harbour pests and to improve air circulation around the plants.
Tools of the trade
Avoid putting any diseased materials into the compost as it can be easily reintroduced back into the garden overtime. After pruning apply a winter wash to your roses, a solution of lime sulphur will help protect against fungal diseases and some common pests. It is good practice to use clean sharp pruning tools and sterilise them between plants. We use a mix of 70% methylated spirits and 30% water to sterilise our tools.
Timing is everything
Aim to prune your roses into a shape that will maximise air flow while minimising the humid conditions where fungal diseases thrive - this is why most people prune roses into a vase shape. The other important aim of pruning is to maximise the shape that will best display as many flowers as possible in warmer months.
Timing of the winter prune is extra important for areas that suffer from frost but not as crucial in coastal regions of Sydney like the Park. If you live in a frost prone area wait until the last frosts have passed before winter pruning your roses.
If you prune too early new growth stimulated by pruning can be burnt by late frost resulting in the plants stored reserves being used for no gain. For frost free regions any time in July is a good time to prune most varieties but not all.
There are several different types of rose commonly found in Sydney gardens. Each has a slightly different winter pruning requirement.
Floribunda, hybrid teas, miniature and dwarf roses should have new growth pruned back by half so the centre of the plant is open ensuring air flow. All crossing canes, deadwood and damaged or spindly growth should be removed at this time too.
Where possible make final pruning cuts to an outward facing bud. You may see references to sloping cuts online or from other gardeners but this can be counterproductive as it creates larger wound area on the plant and can result in damage to the bud if not done with care. For all roses, I would recommend normal straight cuts 10 mm above an outward facing bud.
Allow for a natural shape
For older varieties, such as Bourbon, hybrid perpetual, China, Noisette and tea roses it is best to prune lightly and allow the natural form to develop. As with hybrid teas it is best where possible to remove dead and diseased growth. Untidy off shoots can be removed or tied in.
Standard roses can be pruned as you would with hybrid teas but not quite as hard. Standards are roses which are grafted onto a long stem. After pruning it is good practice to inspect the stake supporting standards as these can rot at the base and may need replacing.
Roses that climb
Climbing roses need to be trained to a support such as a trellis or arbor. If your climbing rose is newly planted only prune to remove broken, damaged or unruly canes for the first two or three years.
This will allow the rose to develop a vigorous framework from which it can be trained. Generally climbing roses are not pruned as hard as hybrid teas and pruning can take place in spring.
Climbers often need canes tied in on their support and this should be done using flexible tape which will not cut into the rose such as budding tape. After pruning, apply a winter wash of lime sulphur to the plant and any support stakes.
Banksia roses are pruned in early summer after most flowers have finished. Like Banksia roses, Cécile Brunner and some old-fashioned shrub roses which flower only once per season are also pruned after flowering.
These roses flower on old wood so pruning in winter will result in no flowers the following season. Banksia roses are vigorous plants and require training when young otherwise you will have a large unruly shrub on your hands.
Carpet roses are small ground cover roses which are the easiest of the lot to prune. When winter pruning carpet roses simply reduce the bush by a third using a pair of hedging shears and the job is done.
Bare rooted roses
Late winter is also a great time to plant roses often bought as bare rooted stock. There are a couple of simple rules when planting with bare rooted roses. First and most importantly do not allow the roots to dry out as these plants have no soil to keep the roots moist.
Bare rooted roses are often wrapped in moist newspaper and it’s best to place them in place them in a bucket of water with some seaweed solution between removing the paper and planting. Bare rooted roses often require a stake for support until the plant develops a root system large enough to support itself.
When planting roses try to find a spot in your garden which receives at least 6 hours of sun per day. A slightly acidic, nutrient rich and free draining soil without competition from tree roots will give your roses the best chance to thrive. Mulching roses is good practice particularly in summer.
Roses are tough plants that can handle a poor pruning cut. The many rules around pruning roses are there to ensure the maximum number of flowers on healthy plants. If you make a poor pruning cut its not the end of the world as your rose will forgive you and still produce the flowers we all love.
Best roses for Sydney
At Centennial Park we use seed free Lucerne straw and compost as mulch. If Lucerne is not available pea straw or sugar cane straw is also good. If you cannot get clean seed free straw mulches, its best to opt for sugar cane straw. Lucerne and pea seeds germinate readily and can create a weedy headache in a rose garden if you aren't careful.
With our humid summers, Sydney is not the ideal climate for roses but by choosing varieties carefully you can have a beautiful rose display even in the most humid Sydney summer.
At Centennial Parklands we have had great success with the beautiful pink flowering hybrid teas Peter Frankenfeld and Queen Elizabeth.
These roses are vigorous and virtually blackspot free. Iceberg roses are probably Sydney’s most popular rose and with good reason. These easy-care floribundas handle our conditions with little pest or disease issues and flower profusely.
Visit the Rose Garden at Centennial Parklands
If you are looking for inspiration and want to see a variety of roses that will grow in Sydney, take a look around the Rose Garden adjacent to Busby's Pond in Centennial Park.
Joseph Maiden planted a Rosarium on this site in 1909 and it has been delighting our visitors ever since. The Rose Garden was renovated in 2003 and many new varieties including Betty Cuthbert, Home and Garden and Blueberry Hill were added to the existing varieties: Double Delight, Pope John Paul II, Merry Maker, Just Joey and Queen Elizabeth.
Share your experience with us by tagging us on Instagram or Twitter @CentParklands #CentennialParklands.