WHEN is a climber not a climber and what are the social things for growing on a wall? Distinguishing between clingers, twiners, scramblers and leaners can be difficult for the novice unsure of the requirements for support, encouragement or training.
While a seemingly limitless range of plants can be grouped under the broad term "wall-plants", relatively few will do the job of growing on a wall of their own volition. Ivy, Virginia creeper and climbing hydrangea are the easiest and most obvious among the select few that will ascend a wall, clinging securely as they go outwards and upwards - and it need not always be a wall: they could be good on a tree trunk if required to enhance a living tree (some would never approve of such action) or even to disguise a dead stump.
This trio in their various forms will oblige equally on a north- or south-facing wall, an important point to remember.
Control - and that is the essence of gardening, the restraining and manipulation of nature - can be easy enough. When the plants have climbed as far as is desirable the gardener ascends a ladder and cuts back growth firmly to prevent an invasion of the root or gutters or to stop too much heavy accumulation on top of a wall.
Clipping back the face of a plant, especially ivy and hydrangea, to keep the growth close to the wall will also be an occasional pleasant task. Imposing one's will on growing things is never a chore.
After that, we are faced with the myriad array which require support in the form of wires or trellis. Some, like the vigorous Clematis montana or wisteria, will take off once the necessary wires are in place and of course they will not restrict their twining tendencies to artificial supports. But in captivity will readily revert to jungle instincts and twine and wind around anything within reach living or dead. So we could contemplate the possibilities of encouraging twiners into suitable trees or large shrubs. Such activity in some eyes verges on slovenliness but I am all for that free and careless look of romance where the boundary between enchantment and dishevelled disoider are dangerously close. Outside my window I admire a somewhat sly and sneaky twiner which has inveigled its way into an azara. The twiner Akebia quinata is a pleasing curiosity much improved by its close association with the socially and physically superior azera. On its own, the Akebia would hardly cause major excitement trained on supports up the wall. Happily it saw a bright opportunity, more promising than the mundane future I had assigned it, and off it went. They are a happy as well as a handsome couple and who am I to come between them?
Then there are all the plants that need tying in and training on support. Roses are one of the most obvious. They will not go up the wall of their own accord but must be tied to supporting wires or trellis. While the desire may be to get the rose high up the wall sooner rather than later, patience is essential if the operation is to yield favourable results. The tendency is often to tie the rose stems in vertically as their growth unchecked will mostly be vertical. This will result in flowers at the top of the stems and bare canes below. The correct and only sensible procedure to produce good growth with abundant flowering is to train the stems horizontally so that vigorous side shoots will he produced in large numbers. This will give a wide, spreading floriferous display.
Lots and lots of things will be happy with a wall as support, without need of wire or trellis, with a little help when they get so big that they may need some assistance in remaining upright. Cotoneaster horizontalis will lean decorously against a wall and mount up without added help. Ceanothus, much used on walls to good effect, does not grow on walls in the wild. However, for better show and display it is grown against a wall, trained and pruned, leaning on the wall for support. When small, such a plant can simply lean but as it, gets bigger some assistance and support become necessary.
The advantage of a wall is that it may provide some extra shelter and warmth, so we may also contemplate plants which would benefit from this protection. The evergreen Magnolia grandiflora, arbutus and myrtle are just a few candidates which could embellish a sunny wall in warmer parts. The possibilities are endless.