A touch of formality never goes astray in a garden. It's surprising how often a clipped hedge or some neat spheres or cubes can instantly pull a rambling, overgrown design together and give it form and purpose.
French gardener Nicole de Vesian showed this brilliantly at La Louve, the garden she made on a stony Provencal hillside after retiring from designing scarves for Hermes in Paris.
Nicole used local plants like lavender, rosemary and santolina grown from cuttings collected from the surrounding countryside and clipped into simple shapes. She loved silver and grey foliage, was phobic about colour and had no interest in flowers.
Local creamy grey limestone sculpted into geometric shapes repeated the forms of the clipped plants.
Closer to home, in his new garden The Kaya at Wildes Meadow (details at end of article), NSW plantsman and gardener Les Musgrave has used terracotta balls to echo low mounds of plants and has included flower colour, spiky leaves and grasses for contrast.
Chinese and Japanese gardeners have long recognised the importance of clipping plants to add structure to a garden's design.
In the Japanese Gardens at Cowra the distinguished Japanese landscape architect, the late Takeshi (Ken) Nakajima, included pink flowering diosma clipped into hedges to imitate the local pink granite.
When training plants for topiary or hedge, grow them to your desired height before you start shaping them.
On our recent holiday in New Zealand I admired the use of topiary in the garden surrounding the restaurant at Mudbrick Vineyard (www.mudbrick.co.nz) on Waiheke Island near Auckland.
The garden has developed over many years to provide fresh food, herbs and flowers for the restaurant and its colourful, overflowing beds and borders are enhanced by formal hedges, spheres and topiary spirals.
If you're looking to add some geometric touches to your garden for the first time, start near the house.
My first formal efforts were a pair of wall germander (Teucrium chamaedrys) hedges clipped to match the sloping walls either side of the front steps.
Each hedge consists of one cutting-grown plant, 150 x 60 centimetres deep and wide and 90cm high next to the verandah, sloping to 20cm. They are amazingly drought hardy and are rarely watered and grow so vigorously they need trimming regularly.
When training plants for topiary or hedge, grow them to your desired height before you start shaping them, but tip prune side shoots from the start to encourage leafiness back down the stem.
If you don't trust your eye to create a sphere or cube, you can buy pre-formed wire shapes or make your own from coat hangers.
Lots of drought-hardy plants respond happily to regular clipping. The smaller the leaf the better, but the chief requirement is the ability to shoot from bare wood, so for this reason avoid cypresses (Cupressus). Lavender is a bit dodgy too: never clip below the lowest leaves.
You also need plants that are easy from cuttings, meaning no worries about the cost of experimenting. Woody herbs like rosemary, rue and artemisia are great, also evergreen pittosporums and you'll never go wrong with box (Buxus).
The Kaya is open by appointment for groups, phone (02) 4886 4050.