Modern climbing roses
Modern climbers have seven- to eight-centimetre, classic-form blooms with canes that tend to be shorter and thicker than the wood of ramblers. (Their scaled-down size makes them suitable for small gardens.) Characteristics are highly variable, reflecting the many rose categories contributing genes to their breeding. Some modern climbers are described as "pillar" roses, because their canes are rigidly vertical and resist twisting and bending, while others take on a "fountain" form, with canes that rise vertically, then cascade down. Three fairly consistent features, however, are a remontant bloom cycle (that is, beginning in late spring, they bloom more than once in the growing season); a wide palette of colours; and a larger flower size than that of ramblers. Grown against a warm brick wall (which creates a micro-climate and advances blooming), a tall modern climber can be the earliest to bloom and extend the season through summer into autumn. Shorter types may be wrapped around a pergola, woven through arbours or draped over fences.
Cane posture is the most crucial factor in achieving maximum flowers. If allowed to grow vertically, climbing rose canes will bloom only at the top and make no effort to set blossoms lower down. Instead, when they are young and still pliable, anchor the canes horizontally to force buds to break along their length, which will produce lateral stems, resulting in a greater number of flowers. (The canes form the supporting structure of the plant, the lateral stems carry the flowers.) It's almost impossible to position rose canes in a true horizontal line, but bending them to any degree will increase flowering.
Pruning Modern Climbing Roses:
Climbers require only light pruning to maintain vigour; it's important to preserve as much of their structure as possible. The long main, or basal, canes can be productive for several years before becoming exhausted.
- Prune at the end of winter, using secateurs or a small pruning saw.
- Remove dead wood from the main canes and lateral stems, and any main canes that did not carry flowering laterals the previous season; also remove twiggy growth that's slimmer than a pencil.
- Preserve younger main canes and secure them in either a horizontal or slanted position.
- Cut back the flowering lateral stems to three or four buds.
- Remove any suckers growing from beneath the bud union. To do this, excavate the soil, grab the sucker down low with a gloved hand and pull it off with a twist.
- Snip off and dispose of any old rose leaves and hips.
Healthy Rose Foliage:
It's smart to grow strong roses that can withstand some degree of fungal disease, such as blackspot. The best preventive measure is to keep the garden clean, removing fallen leaves and any decaying or diseased foliage on a weekly basis. Spraying canes with dormant oil in spring before buds break can also help. After leafing out in May, for ongoing control, spray foliage every seven days with one teaspoon (5 mL) of baking soda dissolved in eight cups (2 L) of water.
Because climbing roses have so much of their wood exposed to wind and cold, their canes are susceptible to winter damage. In Zones 4 and lower, harsh winters with temperatures below –20C will kill substantial amounts of unprotected rose canes; their crowns may survive, however, and produce vigorous new growth in the spring.
Wrapping the canes with any windbreaking material, such as a heavy tarp, helps preserve them. For even better protection, first bundle the canes with insulation sheets (from a building supply store), then wrap in a garden tarp.
Click here to read about year-round care.