Most modern climbing roses are the result of a long history of hybridization. Wild species roses are very tough but have single petals and a single bloom period. The early roses were not as plagued by diseases as the modern hybrids. As newer varieties were developed for more petals, longer bloom periods and better fragrance, other qualities were lost. In recent years climbing roses have been developed to have the disease resistance of the early species.
Buying climbing roses that have been certified as virus-free is the first step in avoiding rose problems. Rose viruses are usually passed during propagation. Roses either survive a virus or they do not. The cell walls are affected during a virus and the stems shrivel. There are no sprays or cures for rose viruses. Cutting back the infected parts will help. Roses that are started from seed or virus-free cuttings will stand a much better chance of remaining virus-free.
Climbing roses also suffer from black spot, rust and powdery mildew. There is no guarantee that a rose will not get a fungal disease, but some varieties do better than others. Nurseries that specialize in climbing roses will have information on disease resistance. Remove infected foliage from the bush and any that has fallen to the ground. If possible, burn the infected leaves. Avoid watering the foliage because this spreads the fungal spores.
Roses are labeled climbers when the canes are extra long. They are called ramblers when the canes are shorter. Ramblers have an arching habit and can be trained on trellises and arbors. Climbers need larger structures to grow on. They come in all the same flower forms as shrub roses do. It is not unusual for climbing roses to have more flowers per bush than other rose types.
Rose diseases can be passed during pruning. Clean any tools with alcohol after finishing each bush. Climbing roses have flower buds along the canes. You will need to leave entire canes intact instead of cutting them back. Remove canes that are inferior, brown or diseased. Leave three to five healthy canes per bush. You will want to remove dead flowers on repeat blooming varieties.
Crowding climbing roses will encourage diseases. Always make sure that there is good air circulation around your roses. Healthy plants resist diseases and insects. Fertilize each fall, and use rich compost around rose bushes. They will need at least a half day of sunshine. Give your roses regular water during the growing season.
Designing With Climbers
Climbers vary from most vines because they do not fasten themselves to structures. They need to be trained or fastened to trellises and fences. When the rose is small, weave the canes through the structure and it will take off from there. The advantage is that climbing roses do not cause damage to surfaces. They will also grow well on hillsides and up trees.