So many plants – so little room! The challenges in small gardens are considerable, but they all have to do with space, such as how to choose plants that won’t grow too large, and how to have continuous color and effect from a limited number of plants. There is one simple way to expand the range of plants being grown and add a whole extra layer of interest to a small space – while taking up almost no room – and that is with wall shrubs. Imagine your walls and fences covered in green, and full of blooms of all possible colors. Instead of hard, drab surfaces, the softness of foliage, and flowers and berries decorating your home and buildings. Sounds great, and it’s easy to do.
Shrubs, Not Climbing Plants
For some reason, when people think about covering walls, they usually choose climbing plants, but these can have limitations, and cause problems. If they cling naturally, they will often damage the surface, and even burrow through the walls. If not, they need elaborate trellising, and they can also get onto a roof or chimneys and need to be cut back at some expense.
A better way to cover walls is with shrubs, which can be attached with a simple system, and which are not rampant like many climbers, and can be chosen for their flowers or foliage. As well, growing shrubs on walls opens up the possibility of growing plants that don’t normally survive in your area. A south-facing wall is warmer and drier that the surrounding garden, so you can grow plants from as much as a zone further south, and ones that need a drier climate too. Always wanted a fig tree? It could be possible if you grow it on a warm wall.
Many people are more familiar with growing fruit trees on walls, in the French style called ‘espalier’, often in complex geometrical forms. These take a lot of training and commitment – great for hobby gardeners but not so good for the rest of us who just want a garden with interesting plants that isn’t too much work. But the same methods in a simplified form can be used for almost any flowering shrub, and the results are spectacular. Any shrub with long, flexible stems can be grown this way, as all you need to be able to do is bend them back a little. If you can bend it, you can grow it on a wall, and imagination is the only limit.
Best Shrubs For Growing Against Walls
Almost any flowering tree can be grown this way. One great example is Southern Magnolia, which is magnificent on a wall. It blooms better, and you can grow it a zone further north than normal if the wall is south-facing. Trees like cherry and crab apple make a spectacular picture in spring. Long-blooming shrubs like crape myrtle are a terrific choice as well, and again you can extend the growing region. Another popular choice is the firethorn, which gives a double display when the white spring flowers turn into orange berries in fall and through much of the winter.
Other shrubs like butterfly bushes and mock orange are great too. You can also grow evergreens – a holly bush will look lovely all year round, and spectacular in fall and winter with a heavy crop of berries. Then there are less common choices, like a Japanese maple, or even a pine tree. As we have already said, almost anything can be grown, but the best choices are plants with a more open growth habit, which means longer branches that can be bent easily and tie to the wall.
How to Grow Shrubs Against A Wall
Step 1: Choose a plant suitable for the light conditions of your wall. South-facing walls are very desirable, as it is there you can grow those plants that find your area a little cold. A west wall is almost as good, and east walls work well too. North walls are more limited, since there is no direct sun at all, but a bright north wall will support a holly tree, for example, and probably a Japanese maple too. Some hydrangeas would work too, especially taller ones like the oakleaf hydrangea, and taller panicle hydrangeas too.
Step 2: Prepare the planting spot just as you would anywhere else in the garden, by adding compost, rotted manure, rotted leaves or just some peat moss. Add a starter fertilizer, which could just be some superphosphate, to feed the root system.
Step 3: Plant your shrub close to the base of the wall, to save space and make it easier to attach it. As well, if you are ‘pushing the envelope’ and trying to grow a warm-zone plant that needs drier conditions, then close to the wall stays much drier naturally.
Step 4: Choose a support system. If you have a wooden wall or fence, then you can choose to just put in nails where you need them, and then tie the stem to the nail head. Usually, though, and certainly if you have brick or stone to deal with, it is better to attach a series of wires across the wall. Insert a row of ring-bolts going up the wall at either end. Space these evenly – 18 inches apart is common, but you can change that depending on what you are growing. Then attach a strong, durable wire to the bolts at one end, and to a wire-stretcher at the other. These are the same as are used for fencing, and they allow you tighten the wires in the beginning, and later, if they stretch a bit, as the often do. The wires need to be tight. It’s a simple DIY job.
Step 5: Start tying in the stems of your bush, spreading them out across the area. As new shoots develop, keep tying them in as they grow. Use a loose loop of soft but durable string, or a loose twist-tie. Notice the word, ‘loose’. If you tie the branches tightly the ties will cut into them as the stems thicken, eventually strangling and killing them. Use as few ties as possible, and keep an eye on them, in case they break, or become too tight.
Step 6: Curving branches flower more. While you want height, there is a great benefit to bending the stems more horizontal and also bending the tips over until they face downwards a little. You stimulate side-shoots, and this encourages more flowering than you will see on a plant grown ‘naturally’. Follow the same basic pruning rules for flowering shrubs – prune spring flowering plants shortly after they flower, and prune summer flowering shrubs in late winter or early spring. This will give you the most flowers, which is of course the goal here.
During the first year or two, pay extra attention to watering regularly, since these spots are drier than the rest of the garden, so your plants will dry out faster. Once established the roots will of course grow forward and get the water they need. Otherwise care for your plant just as you would if it was growing out in the open garden.