Creating A Coastal Garden

The key to success with a coastal garden is to create protected pockets and a gentler microclimate within a tough macroclimate.

Like a trifle, a coastal garden comes together layer by layer.

Gardening at the coast is not all moonshine and roses. Added to that, our coastlines differ from east to south and south to west, from subtropical to Mediterranean to arid. There are also different rainfall seasons and different endemic species. All, however, are buffeted by strong salty winds, have sandy, poor soil, and experience periods of drought and heat.

Design thoughts

In pristine coastal areas you can simply grab the hose, water the ground and wait a while. Unless the building contractor has completely destroyed all the virgin growth on your property, something will come up that belongs there and that you can love.

The endemic plants will in time appear again from old seed banks lying dormant. This is especially true of the West Coast, with its natural diversity of pretty coastal plants that show their beauty every spring after good winter rains.

But even if this is so you might want a little more from your coastal garden, in which case you need to work with a plan. When you begin your coastal garden, work from the seaward side back towards the house and think about a trifle – layer upon layer. The layers should go from small and tough on the seaward side to bigger and more sheltering the closer you get to the home.

The frontline of your coastal garden

Frontline plants are the first layer of your ‘trifle’ and should consist of hardy groundcovers and small, spreading and herbaceous shrubs that will fight the wind. These are usually patches of colour that serve as a living protective mulch around the roots of other plants to keep them cool and keep the ground damp for longer, while also binding the sandy soil.

They include:

Gazania rigens var. uniflora

A very tough groundcover for full sun or semi-shade, it has silvery leaves with bright yellow flowers with a matt-forming growth habit. It is excellent for landscaping harsh areas.

Arctotis spp.

Arctotis is a genus of about 40 – 50 species of flowering plants in the family Asteraceae, native to southern Africa. Some species have been developed into colourful hybrids with attractive yellow, orange, red or white daisy-like flowers.

Carpobrotus edulis (sour fig)

This is a miracle plant. A succulent groundcover, it is used extensively as a soil binder, dune stabiliser and fire-resistant barrier, and is easy to establish using unrooted cuttings and very little water.

It forms a dense mat with trailing stems rooting at leaf nodes, has thick and juicy leaves, and produces large, showy yellow flowers that fade to pale pink in late winter and spring, followed by fleshy, edible fruit with a sour taste. The juicy leaves have many medicinal qualities, like healing mouth infections or skin problems.

Carpobrotus deliciosus

This is another widespread species with purple, pink or white flowers and sweet fruit suitable for making preserves. Nurseries often stock it either as small plants in seedling trays, or as rooted cuttings in large polystyrene trays.

Plectranthus neochilus (lobster flower)

Here is another miracle plant that can be established by using unrooted cuttings (plant them in rows just as you would do with lawn runners, and keep the soil moist until rooted). Otherwise use small plants, which are readily available in seedling trays. This fast growing, evergreen groundcover is suitable to a wide range of climates and will even grow in dry shade. The leaves are ovate, partially scalloped and feel like felt. The flowers are purple spikes resembling those of a lavender bush. The strong aromatic odour the whole plant gives off is believed to scare many pests away, and urban legend has it that it will even keep snakes away from the house.

More frontline plants to consider

Felicia spp., Mesembryanthemum, Lampranthus and other vygies, statice (Limonium perezii), wild rosemary (Eriocephalus africanus) and Pelargonium species.

The pioneers

These are the large shrubs or small trees that grow fast and provide windbreaks and shade to protect the less hardy plants. Consider the following characteristics of true pioneers when you decide what to plant: the leaves can be leathery, sometimes even grey and woolly, scaled, succulent or full of thorns – all an indication that you are dealing with tough plants.

Three of the best for everywhere:

Brachylaena discolour (coastal silver oak)

The large, leathery, deep-green leaves with their silvery white undersides flashing white in the sun when the wind blows are an extremely attractive feature of this fast-growing, bushy and multi-stemmed shrub or tree. Masses of creamy white flowers in spring attract bees and insects. This is a perfect choice for a medium to large protective hedge at the coast, as it responds very well to formal pruning.

Tarchonanthus camphoratus (camphor bush)

A dense bushy shrub or small tree with aromatic, leathery, greyish-green foliage, the camphor bush produces small sprays of creamy flowers in winter, which are followed by very attractive fruit with a cottony covering. This is a fast-growing plant with a fairly aggressive root system that binds soil. It is perfect to plant in numbers as a protective windbreak or formally pruned hedge on the garden’s borders.

The camphor bush can also be trained as a single specimen into quite an attractive little evergreen tree, as it develops a very characterful main trunk if side growth is constantly removed.

Virgilia oroboides (blossom tree or keurboom)

This is an extremely pretty little tree that grows at the speed of lightning. It is evergreen and produces a profusion of sweetly scented, rose-pink, pea-like flowers in spring. Bear in mind that this is a pioneer plant that does not live all that long (15 – 20 years), but it will beautify your garden while you wait for other plants to mature, acting as a nursemaid for those not as hardy to wind.

The framework trees for a coastal garden

Now you can start with framework plants, which perhaps need a little more love, attention and patience to settle in. Owing to the fact that most coastal gardeners are always in search of wind-hardy trees to plant, especially in the treeless coastal areas of the Western Cape, here is a reliable list of indigenous trees that will work in these conditions:

Curtisia dentata (assegai), Dombeya rotundifolia (wild pear), Dovyalis caffra (kei apple), Erythrina caffra (coast coral tree), Ficus sur (broom cluster fig), Halleria lucida (tree fuchsia), Kiggelaria africana (wild peach) and Rapanea melanophloeos (Cape beech).

The cherry on top

Once you have tended to the frontline, the fast pioneers and the permanent framework, you can basically plant what your heart desires in their shade or protection as long as it is logically suitable to the climate. Such is the key to success in a coastal garden!

Good advice for your coastal garden

The salt spray, poor sandy soil, tearing wind and heat that dries out everything will all test a gardener’s patience to the limit. Here are some useful tips:

Leave all natural growth, even if it spoils your view. It provides a natural windbreak that will keep wind and salt spray away from your house and garden. Rather than cutting everything down, make a peephole in the natural growth that will frame your view to the sea. That’s much more dramatic and eco-friendly.

Observation: Local authorities caring for public open spaces close to the beach often make the mistake of simply hacking across the top of endemic vegetation (white milkwood trees included) at the behest of home owners complaining that they spoil their view. This creates low, dense growth and hiding space for thugs and poachers. Feathering their crowns and cleaning them up at the base is a better idea.

If there is no natural plant growth, you must plant a few pioneer plants without delay.

A solid garden wall on the side of the prevailing wind is not a good idea. It will create wind resistance, and the wind will then simply blow more fiercely over and around the wall. Rather employ plants or other fencing material such as wooden poles, laths and mesh if you want to enclose the property.

Coastal soil is sandy and nutrients leach out very quickly. Spare no cost in preparing the soil well with ample loads of compost and water-retentive products. Afterwards provide regular doses of fertiliser and water until the new plants are well established.

Light-weight mulch such as coarse compost or small bark chips does not last long in the sun and wind. Use landscape fabric (weed matting) to cover the ground – fasten it securely with lengths of galvanised wire bent in the shape of hairpins. You could even span it over a newly prepared bed before planting. Simply use sharp scissors to cut slashes into it through which you can plant your plants. Afterwards pack a heavier layer of mulch on top, such as river pebbles, coarse gravel, peach pips or shells to capture humidity for longer.