It’s time now to plant, prune and take precautionary action against pests and diseases. Paying attention to roses in winter can greatly improve their performance come spring and summer. WHERE TO PLANT
Roses grow best with plenty of sun. They also need some air movement to minimise pests and diseases. The best soil for roses holds plenty of moisture and nutrients, which means a clay-based soil can be a good thing. Soil that is too light (sandy) or very heavy (clay) can be improved by adding compost.
Many of the roses sold in winter are known as ‘bare-root’ roses. This means they have been grown in the open ground and then dug up for winter planting. The roots are wrapped with protective packing or planted into pots before being transported to the garden centre. Often, barefoot roses are transferred to pots once they reach the garden centre. When planting bare-root roses in winter, remove the wrapping plus any packaging material surrounding the roots. Soak the roots in a bucket of water for an hour or two before planting. When planting pot grown roses in spring: carefully remove the container, leaving the new root growth as intact as possible. Dig a generous planting hole large enough to fit the roots without forcing them. Add controlled-release rose fertiliser or sheep pellets to the hole. Sit the plant in the hole so that the roots are growing downwards and the crown or bud union (the place were the shoots grow from the main stem) sits above ground level. Fill the hole with soil and tread firmly. Water thoroughly.
July is pruning time for most bush roses, but wait until August in coldest climates. Using a clean, sharp pair of secateurs, remove dead or decaying wood, branches crossing over each other or crowding the centre of the bush. Make cuts about 5mm above an outward facing bud. This is where the new growth will sprout in spring. Find out more about rose pruning at www.gogardening.co.nz and be assured, it’s hard to kill a rose by pruning it!
WINTER CLEAN UP
Fallen rose leaves provide a perfect refuge for overwintering pests and diseases, so clearing them away is one of the best ways you can reduce infection in spring. Clean up after pruning, then spray your roses and the ground around them with copper to knock fungal diseases. Horticultural oil, if sprayed in late winter just before bud break, will kill aphid and scale insects as they hatch from their eggs. Early winter spraying is less effective as the eggs are resistant to the oil.
Applying copper in winter significantly reduces disease problems during spring and summer. Yates® Liquid Copper Fungicide is an easy to use copper based solution for the prevention of many diseases on fruit, vegetables, roses and other ornamentals. Its unique formulation provides advantages over conventional copper fungicides with ultra-fine particles providing a dense barrier to disease infection without leaving any unsightly blue residue. Find out more at www.yates.co.nz. WIN ONE OF FIVE 200ml bottles. Entry details below.
LEFT: Compact floribunda rose ‘William PJ McCarthy’.
Clean up after pruning to remove old leaves that harbour diseases like blackspot.