THE snow on the mountains and frost at night means it's time to get your roses ready for winter hibernation and it's not hard to do if you apply some focus and follow a few simple tips.
Keep in mind that our mild West Coast climate means that almost all roses grown in our region are hardy for our climate, so there is no big rush to get them ready nor is there any real concern that our roses will freeze and die over the winter, not including roses that have poor health to begin with.
The first thing I recommend to prepare your roses for winter is to lightly prune them back by no more than one third of their total height. This light winter pruning of roses prevents wind-rocking and snow damage and also removes some of the rose's leaves, which is the next step in the process. Remember that when you cut your roses back, prune a quarter inch above a bud using a square cut and please, no sloping or angled cuts. I have spoken previously about making angled versus square cuts when pruning and the reality is that angled cuts do not prevent winter damage or stop the rain from sitting on the end of the stem, nor do the angled cuts look visually appealing.
Cutting back roses by one third of their total height is recommended for all roses except miniatures, groundcover roses and dwarf shrub roses. All other roses, including climbing roses, should be pruned in the recommend manner.
For climbing roses, prune back only the current year's extension growth by one third, meaning those long new shoots jutting out into the air. Leave the structural branches alone until spring.
The next step in preparing your roses for winter is to remove all leaves from the plant and the soil.
To prepare roses successfully for winter it's important to remember that roses are one of the most pest-and disease-prone plants grown in our region and therefore to prevent disease infestation next spring you must prepare your roses well this winter.
Rose leaves can be picked off by hand, which is necessary in most instances, or blown off with a blower. The purpose of removing all of the leaves is to remove disease spores that overwinter on the leaves.
Leaf removal requires a meticulous effort to pick off and remove every single leaf, green or not, from the plant and the soil below the rose. By removing leaves infected with rose rust, powdery mildew and black spot, the amount of disease causing spores available to reinfect the rose next spring is dramatically reduced or eliminated completely, so your roses start spring growth clean.
Most home composters do not generate enough heat to kill disease spores so I recommend putting infected rose leaves into the green waste, not the garbage.
Once the rose has been pruned and picked clean, the last winter preparation task is to apply mulch six to eight centimetres deep to protect the soil and the rose's roots from winter weather.
The choice of mulch material depends on individual preference and the current state of health for your rose's soil.
If you have a weak rose or poor quality soil then choose an animal manure to apply to the rose beds for winter. This will allow the natural antibiotic benefits of animal manure to slowly leach into the soil over the winter to be available for next spring's growth.
If you have healthy roses and good soil, choose bark mulch (composted or natural), shredded wood chips, shredded leaves or any other organic material that decomposes. The purpose of the mulch is to improve the visual presentation of the rose beds, to add organic matter to the soil, improve the quality and quantity of microbial life, lessen freezing of the soil and to prevent weed growth. Do not dig in the mulch next spring, just leave it in place to do its work.
I do not recommend spraying roses with dormant oil, lime sulphur or any chemical fungicide because in our rainy climate, all rose fungicides are washed off the rose stems before they can do any good. And chemicals that wash off are leached into ground water and ultimately the ocean, creating dead zones and killing other life.
If you follow the three simple rose winterization tasks of prune lightly, pick off all leaves and mulch the soil, then you have done all that is needed to prepare your roses for winter.
Todd Major is a journeyman horticulturist, garden designer, writer, consultant and organic advocate. For advice, contact him at [email protected].
