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.
Lawrence Johnston is a very vigorous old (1923) climber to 14’ that has had almost no dieback for me. It has large, blousy, rich yellow semi-double flowers with attractive stamens. The fragrance is not strong, but is very pleasant. It has one long bloom period, is water thrifty and easy to grow.
“Victorian Memory” is a remarkable rose of unknown origin. Dr. William Campbell of the former High Country Rosarium gave its name because its true identity was never discovered. It can climb 15’ to the second story windows. The flowers are loosely double, lilac-pink and they hang downward somewhat. The fragrance is odd but many find it quite pleasant. It has good repeat bloom, especially if deadheaded. The canes are nearly thornless; it has good disease-resistance and no winter dieback in our area.
New Dawn was the first rose ever patented in America, in 1930. It is a very thorny and hardy climber to 6’-10’ with glossy, healthy foliage. The flowers are blush pink, often appearing white, double and having a sweet, fruity fragrance. It has a profuse first blooming, repeating through the season.
Henry Kelsey is a modern Canadian climber to 6’-8’ with thorny canes and good disease resistance. It is the best red climber for cold climates. The flowers open true red and age to a rose red; they are loosely double with showy golden stamens. Repeat flowering is good, especially with deadheading. For me it has been very tough, drought-tolerant and cold hardy with very little dieback.
William Baffin is the most cold hardy climbing rose to date to zone 2. It is very vigorous and can be made to climb or will make a huge shrub 8’x8’. The flowers are strawberry pink, of a loose, informal shape and they repeat well. It is very disease resistant and easy. In fact it can overwhelm a small trellis.
John Davis is a modern Canadian climber with beautifully formed semi-double, rich pink flowers which have a good fragrance. It blooms freely from June to frost even in my difficult conditions of blazing west sun and blasting west wind. It is also very healthy. I can’t tell about height yet; some say a short climber, others say tall.
These are a good sampling of the hardiest climbers in my experience.There are, however, others that are very worth trying.