Growing Climbing Roses on Walls and Pergolas

Start with the right support

Climbing roses do not cling. Unlike ivy or Virginia creeper they have no aerial roots and no twining stems, so every inch of height they gain has to be held there by you. That is the first thing to accept, and the first thing to plan for. A wall-covering rose in full leaf carries real weight, and a mature plant can pull a flimsy trellis away from the brickwork in a single windy night.

Before you buy the rose, decide on the armature. On brick or stone, galvanised vine eyes screwed into the mortar at 45–60cm intervals and strung with 2mm galvanised wire will serve for decades; heavier ramblers are better with 3mm wire and a turnbuckle at one end so you can keep the tension up. Space the horizontal runs about 30–40cm apart and keep the wire roughly 5cm clear of the wall so air can move behind the foliage. That small gap does more against blackspot than most other measures you can take.

Arches and pergolas need the same honesty about strength. A wooden arch should be bolted down, not staked, and a pergola post of at least 10cm square is sensible for a vigorous climber. Fit the support, then wait a few weeks, then plant.

Choosing the wall, arch or pergola

A south or west-facing wall is the warmest site and suits most climbing roses, including the tenderish old-fashioned sorts. East walls are gentler: morning sun, cooler afternoons, less scorch, and they suit pale blooms that fade in strong light. North-facing walls are genuinely difficult. Only the toughest will manage there, and even then you should expect fewer flowers and more disease.

The other thing to remember about any wall is that the soil at its foot is a desert. It sits in the rain shadow of the building, it dries out fast, and it is often full of builder's rubble. Plant your rose 40–45cm out from the wall, lean the stems gently towards the support, and angle the roots away from the masonry so they grow into open ground. Add plenty of well-rotted organic matter to the planting hole and water it in thoroughly, even if rain is forecast.

Training for flowers, not just height

This is the single most useful piece of knowledge in climbing-rose growing. Left to itself, a stem grows upwards, puts out leaves along its length and produces a disappointing tuft of flowers at the very top, out of sight. Bend that same stem towards the horizontal and it will break into flowering sideshoots along its whole length, because the slower flow of sap encourages flower buds rather than extension growth.

• Fan the main stems out from the base like the ribs of a fan, keeping each one at roughly 30–45 degrees from vertical.
• On an arch or pergola upright, spiral the stems around the post rather than running them straight up.
• Keep the centre of the plant open so air and light reach the foliage.
• Allow room for next year's new canes before you need them — aim to leave a third of the space free each season.

Run stems along pergola beams too, tying them loosely so they can flex in the wind without chafing.

Tying in: small details that save heartache

Use soft jute twine, or purpose-made rose ties with a soft inner face, and never bare wire. Tie in a figure-of-eight so the stem sits in one loop and the support in the other; this holds the rose firmly without strangling it as the wood thickens. Work at 30–45cm intervals, and check the whole plant after the first autumn gales.

The best time to train new growth is late summer and early autumn, while the canes are still supple. Old wood becomes brittle and will snap if you force it. If a cane resists, tie it where it wants to go and bend it a little further next month.

Feeding and watering on a dry wall

Water deeply and less often. Two full watering cans per plant, poured slowly at the base, once a week through dry spells in the first two seasons, is far better than a daily sprinkle. From the third year the roots should be down far enough to look after themselves in all but the driest summers.

Feed in late March as growth starts, then again in early July after the first flush of flower, using a rose fertiliser at the rate on the packet. Mulch 5–7cm of well-rotted manure or garden compost over the root area each spring, keeping it a hand's width clear of the stems. Deadhead regularly through the season to keep repeat-flowering varieties going, but leave a few hips in autumn for the birds.

Pruning and the yearly rhythm

Repeat-flowering climbers are pruned in late winter, ideally January or February while dormant. Shorten the flowering sideshoots to two or three buds, tie in the best new canes from the base, and cut out the oldest wood to keep the plant young. Ramblers that flower once, such as 'Albertine', are pruned straight after flowering in late summer: cut out the wood that has just flowered, right back to the base, and tie in the new canes that will carry next year's blooms.

Clear fallen leaves from around the base through the season to reduce blackspot, and renew the twine each winter while you can see what you are doing. Check the wires and the pergola fixings at the same time, tighten what has loosened, and treat the timber if it needs it. Do that much, and a bare wall becomes a scented, generous thing within three or four seasons.