Arid Landscaping

By admin2
Updated: December 3, 2020

In many parts of the world, current climate conditions make it more and more difficult to support a traditional landscaping plan involving huge, thirsty lawns. According to the Cambridge Dictionary ‘arid’ means: “Very dry and without enough rain for plants”. I beg to differ…

Building an arid landscape gives landscapers the opportunity to include many different plant species with flowers, some of which are indeed found in deserts.

The defining characteristic of an arid climate is lack of moisture. The soil is dry, the air is dry, and yearly precipitation is very low. In some arid climates, evaporation rates exceed precipitation, leading to a net moisture loss. One thing all deserts have in common is that they are arid or dry.

Any landscape can be beautiful, even an arid, dusty area with rocky outcrops and little water. This type of landscape needs little maintenance and the reduced water consumption also incurs lower costs.

Some arid zone habitats include tall shrubs, heath, grasslands, sandy areas and rocky areas. Tall shrub areas have small eucalypt, mulga and acacia trees. Heath areas are covered in bluebush and saltbush plants. Spinifex grass often grows in arid  zone grasslands. Another style incorporates building sand dunes and of course, the more common arid garden, which features rocky areas including a dry riverbed.

TIP: In a real river, larger rocks are typically found along the outsides of river bends; try to mimic this effect for the most natural look.

Arid landscapes are full of natural rock features, which provide good options for climbing plants and interesting angles. Rock gardens for desert landscapes tend to look even more aesthetically pleasing if you introduce two to three different cacti species into the mix. Keep your cacti clusters small but prominent.

Gravel can be an excellent material for winding paths. Combine smooth gravel and stones with aged rock, and you have the perfect mix of colour and texture. Aged rocks provide a lot of texture and colour, while the stones help with balance and proportion.

Build rocky outcrops. Use any slopes that occur naturally in the garden to create terraces by building miniature retaining walls to shore up the slope.

TIP: Create slopes on naturally flat ground by building berms or rounded mounds of soil/rock. Use the 5:1 ratio as an average because you should vary the slope to create greater interest. Give the berm more than one peak and avoid putting the highest peak in the centre of the berm. Berms are more interesting if they are shaped like kidney beans or crescent moons.

Obtain rocks of basalt, sandstone and granite in natural shapes. Position the bottom layer of large rocks where you want the rock feature and bury them up to 50 per cent in the sand for stability. Place other rocks on top, leaving spaces to fill with soil for planting.

TIP: If you think erosion is going to be a concern in this project, ringing the berm with stone edging gives you something of an insurance policy: the edging will trap any soil that washes down the slope. Be mindful of potential drainage issues.

Desert plants can be classified into three main categories: cacti and succulents; wildflowers, trees and shrubs; and grasses.

Cacti and succulents have differing leaf colours of blue, silver and shades of green. Add texture and grow to different heights in an arid garden, which in turn adds interest when viewed from different angles. They require little to no maintenance yet appreciate attention and will reward effort with stunning flowers.

Did You Know: Although the leaves appear to be silver or blue, they’re actually various shades of green. Tiny surface hairs or scales usually coat the green leaves, keeping the foliage cool by reflecting sunlight up and away from the plant. Other plants may be hairless but grow with a thick, waxy coating that helps retain moisture in the leaves.

You can design your landscape using only plants with silver and blue foliage, or mix them – they look especially striking when combined with bright or clashing colours such as orange, yellow and red.

A succulent plant to consider using in your arid design is aloes. One of the best known of the aloes is aloe vera, which is used medicinally and cosmetically. The sap from this plant is useful for burns and is available in many cosmetics, shampoos and ointments. There are hundreds of varieties to choose from. They grow naturally in arid and semi-arid areas and are well-suited to dry climate gardens in Australia. They will tolerate low fertile soils and will survive infrequent watering, as well as salt air and extremely cold temperatures. They will grow in semi-shaded areas but prefer a position in full sun and even grow well on exposed dry hillsides. Aloes will bloom every year and do not die back after flowering.

Dracaena trifasciata – you might know it as Mother in Law’s Tongue or Snake Plant. It is always on the plant list in an arid garden.

An Australian native that looks stunning in an arid garden is Bower Wattle – Acacia cognate. It is a tree/shrub species that is endemic to south eastern Australia.

One cannot forget to include the Grass Tree – Xanthorrhoea australis, which is a distinctive looking, slow-growing plant, ranging from those without visible dark trunks to tree-like specimens up to 6m high.

The Callistemons or Bottlebrush trees also work well. They’re colourful, inexpensive, low-maintenance, drought-resistant and readily available.

A ground cover, Banksia spinulosa ‘Birthday Candles’ has orange and gold flowers appearing in autumn and winter. Being a dense and compact small shrub it is perfect for rockeries and smaller gardens when mass planted for dramatic effect. For colour in spring, summer and autumn, plant the small clumping perennial Anigozanthos – Kangaroo Paw, again in drifts for impact.

Grasses add movement and interest in the slightest of breezes. Their leaf colours can complement or contrast with your plant choices. Consider using Pennisetum – dwarf purple fountain grass because it’s hardy, compact, low maintenance, with warm burgundy foliage and creamy-pink fluffy foxtail plumes.

Festuca glauca – blue grass, forms clumps of slender, blue-grey fine foliage and it makes a fantastic filler in the landscape. Its compact growth habit makes it attractive next to low shrubs, and several plants can be planted in groups to enhance their striking effect in-between rockeries or borders.

Commonly, landscapers use the various cultivars of Cordylines, Liriopes and Lomandra planted in swathes for full effect.

Did You Know: Many desert plants store water in their stems. For some species, this stored water enables plants to survive for years on moisture gathered during a single rainfall. Some cacti and succulents feature ribbed stems, which expand as plants absorb water and contract as plants consume water. Cacti have a waxy covering or skin, which seals water into the plant so it doesn’t evaporate.

One purpose of the spines on cacti is to protect the plant against creatures that would try to open the stem to consume water reserves.

Perversely, a rain garden is a great option for the end, collection point or lowest point in your landscape in some areas, even though it’s an arid garden. A basic rain garden is a 150mm to 250mm deep depression (like a small pond) filled with plants that can tolerate occasional flooding. During sudden heavy downpours, water collects in the garden and filters into the ground, usually in a matter of hours. Rain gardens are a natural solution to common drainage and stormwater problems and are recommended by many councils across Australia. Contact your client’s local council before quoting for assistance and their preferred process and procedures around rain gardens.

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