Many plants – not only climbers – look well against a wall, especially if you’re lucky enough to have mellowed brick or stone
in your garden. But while some plants will thrive, the foot of a wall is essentially quite an inhospitable environment, and anything that struggles with heat, drought or strong sunlight need to be avoided.
Prepare your soil
Soil on the foot of any wall is invariably poor and dry, because the wall deflects rain while foundations and buried rubble take in a number of the available moisture. If you’ll be growing true drought-tolerant plants, it’s enough simply to work in some well-rotted compost to reinforce what’s there already.
But in the event you plan to grow sun-loving fruit, wall shrubs or climbers, dig out all of the soil and rubble right down to a depth of 18ins, then replace it with good-quality topsoil mixed 50:50 with well-rotted organic matter, to make a bed 2ft wide that runs the whole length of that component of wall.
Growing semi-tender wall shrubs
A south-facing wall soaks up sun and stores warmth even in winter, so it’s possible to grow semi-tender plants that may not survive within the open garden. To profit from this effect, train slightly delicate shrubs flat over the wall, tying them to netting, trellis or horizontal wires supported by nails. Plants to exploit include phygelius (cape figwort), pineapple broom (Cytisus battandieri), Fremontodendron californicum, ceanothus and Carpenteria californica.
Choosing climbers
Roses: Grow warmth-loving climbers Rosa “Mermaid”, Rosa “Madame Gregoire Stachelin” and Rosa banksiae cultivars (all very large-growing). Or in a smaller space, train the huge, very fragrant-flowered, old-fashioned bush rose “Madame Isaac Pereire” out flat against the wall.
Woody climbers: Opt for the trumpet vine (campsis), trachelospermum, jasminum, purple grape vine and tri-coloured Ampelopsis brevipedunculata “Elegans”.
Pick warmth-loving fruit
Grapes and figs both benefit from the slight root restriction created by a bed with a wall along one side and a path at the other, while warm, sunny conditions help considerably with fruit ripening. Kiwi fruit also thrive on this situation (plant a female and male or choose a selection known to provide both female and male flowers to verify pollination).
Fan-trained peaches, nectarines and apricots produce heavy crops on south-facing walls, and it’s easy to offer protection to the notoriously early flowers from frosts by draping plants with fleece overnight (remove it by day to permit insects access for pollination).
Pears ripen reliably on this situation – to make best use of the gap, opt for gourmet varieties similar to “Williams’ Bon Chrétien” and “Doyenné du Comice”.
Drought lovers
For a showy yet low-maintenance, year-round bed, choose drought-loving perennials comparable to hardy hippeastrum and nerine, bearded iris, osteospermum, sedum, crocus and tulip, set against a backdrop of drought-proof climbers or wall-trained shrubs.
Sun-loving annuals and bedding plants which include argyranthemum and pelargonium need good soil, frequent watering and liquid feeding, plus regular deadheading to thrive, so avoid those if you’re wanting time. Hardy annuals sown straight into the soil are essentially the most self-reliant, but even they’ll need some watering in hot, dry weather.
Looking after your plants
Plant semi-tender shrubs and climbers in May after winter is past, in order that they have an entire summer to get established before having to outlive a chilly spell. Water plants (even true drought lovers) from the time they’re first planted until they may be established and growing well. Mulch and feed fruit and vigorous climbers or shrubs in late April/May. Liquid-feed fruit, and have the ability to water regularly while crops swell and ripen if the soil is extremely dry, or install an irrigation pipe.
Solving problems
Ants enjoy hot, dry, sunny conditions, and in the event that they nest, they undermine the roots of recent plants. Flush nests out with a lot of water or specialised products. Powdery mildew often affects certain plants growing on hot, dry walls in late summer and autumn, worsened by over-dry roots, so water well on the first signs. Pick off badly affected leaves or spray with fungicide.
Plant of the week
Kaffir lily (Clivia miniata)
If it is kept too hot, it won’t flower, so it’s infrequently sold as a home plant. But now we’re turning the warmth right down to save costs, it’s worth on the lookout for since there aren’t many exotic-looking, winter-flowering plants that thrive in thrifty heating. It’s also easy to grow, given a couple of basic rules. In winter, keep it in a groovy room at 40-50°F without feed and only minimal water. Increase watering in spring, then in summer keep it as cool as you may and in light shade (a north windowsill indoors is ok, because it will scorch in full sunlight). Water fairly generously and apply occasional doses of well-diluted liquid tomato feed until autumn.
What to do within the garden this week
If your yew, privet or box hedges are overgrown, curb one side hard now. Pull ivy and tree seedlings out of hedge bases.
Assemble raised-bed kits or put money into large patio containers to create a potted kitchen garden near the back door.
There’s still time to plant bare-rooted shrubs, hedging plants, roses and fruit – you may continue until mid-March.
Complete winter digging when the elements permits. On the way to make an early start, cover prepared soil with black plastic so it warms up without sprouting a covering of weeds.