The Canadians, like their English and French ancestors, have a great love of roses. However much of Canada is in zones 4, 3 and even zone 2. Therefore many of the hybrid tea and floribunda roses bred in modern times have not been tough enough for Canadian gardeners. So the Canadians set their own federal agriculture department to work on breeding roses that succeed in Canada. Not only do these roses do well north of our border, they are very successful in Colorado, even in our higher elevation environments. Our 10-20 below zero winters and dramatic temperature changes can kill or significantly injure more tender roses like the hybrid teas and floribundas. So gardeners in Colorado who don’t have time to remove large masses of dead canes, hill soil around the canes to protect them for winter, and who have less inclination to spray and fertilize frequently, find the Canadian-bred roses provide a rewarding and easy-care alternative.
Many Colorado gardeners have been frustrated in their attempts to grow climbing roses. The main problem seems to be that the tall canes die back and though they may bloom, they look like shrubs, not climbers. We are green with envy of the European and Californian gardens with roses cascading over and festooning pillars, walls and bowers. Why can’t we achieve this? I think we can, but not without a very discriminating approach. First of all we must realize that our cold temperatures and especially the rapid cold-hot-cold changes, and our drying winter winds are death to all but the hardiest rose canes.
Henry Kelsey (1984 Kordesii cross) is an Explorer Series rose from Ag. Canada that is hardy to Zone 3 and is considered by many to be the best red-flowered climber for cold climates. It is very vigorous and grows strongly even in lean soils. Whereas it can be grown as a low arching shrub to 4’, it excels as a short climber to 8’-10’ and looks especially good trained down a split-rail fence. The flowers are semi-double with prominent golden stamens, opening a luscious deep red and fading to a pinker medium red. The fragrance is light but pleasant and the clusters of flowers repeat from June until frost. Where I have grown it in a very low water area over the last five years it has performed well and has not died back on the trellis, but repeat flowering is intermittent rather than continuous. One of the truths of xeriscape is that not all plants that grow well on low water, flower as well. Sometimes just one or two deep waterings during bloom time will make a big difference in flower production.
At the end of last season I wrote about how to succeed with climbing roses in Colorado. Besides winter watering and careful siting out of the worst wind, the most important factor is the choice of very cold hardy roses that are grown on their own roots. The books may say we are zone 5 but when the temperature drops from 50 at noon to 5 at two a.m., we better hope our rose is zone 4 or even zone 3 hardy. With climbers this is even more true because if the canes die back to two feet the rose may still bloom but it won’t function as a climber that year. Here are a few of the toughest and most cold-hardy climbing roses for Colorado.
After last November’s 77 degree cold plunge to 13 degrees below zero, most roses suffered die-back, some died to the ground and some died completely. But there were roses that had only minimal damage and some that will bounce back with a good show of vigorous growth and generous flowering this year. Here are some observations and conclusions about growing sustainable roses in Colorado.
Roses are cane shrubs, similar to blackberries and raspberries. Their wood has a pithy center and is not as hard or as strong as a lilac. Consequently roses are more vulnerable to insects, diseases, desiccation and cold, but another consequence is that they can grow and regrow much faster than woody shrubs like lilac and viburnum.