The dry allure of the xeriscape

Gardening in the driest or windiest parts of the country? Xeriscaping may be the system you’ve been looking for.

We’ve all heard about water-wise gardening – the practice of choosing, grouping, and placing plants according to their watering needs in order to maximise the efficiency of the little water you have.

But what if you had almost no water at all? Or – and many South African gardeners fall into this category – you have no water, and you also have to put up with dry, salty winds throughout the year? Nothing’ll grow ’round your spot, will it?

Well, not all heroes wear capes. Some of them wear xeriscapes.

Xeriscaping takes the principles of water-wise gardening to their ultimate conclusion. In xeriscaping, you choose your plants – usually desert-adapted species – for their suitability to your climate, and you design the shapes and hard elements of your garden to ensure run-off so that your plants won’t drown when they do get a little too much moisture.

It’s not for everyone. If you’re gardening in the wetter parts of the country, it’s definitely not for you. But if you’re in an arid area – well, let’s party.

The basics

Xeriscaping. The word is a composite of the terms ‘xerophyte’ and ‘landscaping’. Xerophyte is the term for plants that have adapted to survive in water-scarce areas.

Some great South African examples would include aloes, euphorbias, cotyledons (pigs’ ears), Portulacaria species (spekboom, great for hedging and background planting), crassulas, lithops (stone plants), stapeliads (starfish flowers), and vygies. In other words, the succulents or vetplante – although, to be sure, there are other plants, like some of the Cape reeds (restios), that’ll stand up quite well to xeriscaping, too. Given that this country boasts the world’s most diverse selection of indigenous plants, that many of our indigenous plants aresucculents, and the fact that many succulents are obligingly easy to propagate, we’re truly spoiled for choice when it comes to plant material for this method of gardening.

What is important, though, is your soil and its preparation. Succulents usually prefer full sun, little or no irrigation, and well-drained soils; they usually don’t give a fig for indulgences like compost, fertilisers, or heavy frost. And they’ll die if you over-water them – I know this from experience. As apprentice horticulturists, some classmates and I tried growing some American cactuses in the boss’s hydroponics tanks. They grew beautifully, and very quickly. Plump, fat, and gorgeous. And then one morning everyone came to work to find that the Americans had spent the night exploding into a mushy mess of gunky goo.

Which, since succulents generally form the backbone of any xeriscaped garden, explains why the system works best in the drier parts of the country: the Northern Cape and parts of the Western Cape, the Eastern Cape and North West Province.

Xerishaping

One way to ensure that your succulents won’t wallow in the wet when it does rain is to shape your planting areas into mounds, and perhaps direct the water run-off into your gravelled pathways, and from there away via the property’s natural drainage. Shaping and contouring is useful, too, for providing visual relief and interesting contours in level, otherwise featureless spaces. But be aware, especially if you’re going to import the soils for mounding, that you need to choose your soils carefully. No compost! No rich, loamy topsoil!

Hard landscaping

Many xeriscaped gardens rely on rocks, gravel, paving, and other hard elements to define shape and spaces.

Crushed gravel, quartz river sand, and even bark chips make excellent mulch, which is useful for shading the soil from the heat of the sun, and for preventing evaporation (bearing in mind that your ultimate aim isn’t to go water-free altogether, but rather to design for water efficiency). Be careful with the bark chips, too: spread them judiciously so that they don’t retain too much moisture around the more water-averse plants – like those American cactuses.

Gravel and sand are also useful design elements if you’re planning a Zen-style garden – which, by the way, can be exceptionally well adapted to xeriscaping.

Many xeriscapes rely for their design success on well-placed arrangements of rocks. As a rule of thumb, local rocks usually work best, probably as a result of the ‘borrowed landscape’ principle: the idea of marrying your garden to its surroundings through visual links with existing features outside the boundaries of the garden. Some landscapers have suggested that rocks provide microclimates in the garden – at night giving off the heat they’ve trapped during the day, and during the day offering shade for some of the more delicate plants – which partly explains why you’re likely to see plants clustering around natural rock formations in undisturbed desert wildernesses.

Zoning

Zoning in xeriscaping is critical. It’s more of a science than an art, since it starts with knowing about the water, wind, and sun-or-shade requirements of the plants you’ve chosen – and then grouping them in those zones of the garden that’ll suit them best. Fortunately, this kind of information is readily available on sites like PlantZAfrica (pza.sanbi.org).

When you’re designing your garden, remember, too, that the space must serve your family as well as your environment – so allow yourself the luxury if you need a patch of lawn for the kids to play on, for your pets, or as a place where you can simply relax. Your local nursery person or landscaper should be able to advise which grass species is the most water-wise for your area. (Hint: it is not, and never will be, the invasive kikuyu, Pennisetum clandestinum.)

Be dry, but bold

Xeriscapes – succulent gardens, if you will – haven’t always had the best design reputation in South Africa. Too many of us remember the circle-of-rocks-with-a-tired-looking-aloe-in-the-middle style of rockery that graced so many old homes and farmhouses back in the day.

But xeriscaping doesn’t have to be bleak and dreary, and it doesn’t have to be flat on the ground, either. There are some fantastic indigenous ‘trees’ like the lovely quiver tree (Aloe dichotoma) and the halfmens (Pachypodium namaquanum) that can create a dramatic sculptural focus.

In the hands of a creative designer, the bold, strong, colourful, and often geometric shapes and textures that characterise the appropriate plants, rocks, gravel, and other elements of this method of gardening can become the raw materials of many an exciting and unusual landscaping project.
Imagine a formal knot garden in the style of the classic French gardens at Versailles, a Zen temple garden, or a Mondrian-style abstract tapestry planted proudly in the earth.

There’s almost nowhere you can’t go if you set your imagination free.