When it comes to the intricate art of topiary, it's important to choose your tools correctly, right down to the species of tree or shrub that you choose to shape. Not every species is suitable for topiary - in fact, only a few can provide the consistency of colour, leaf density, pruning tolerance and evergreen growth that creates the classic topiary look. The following tree and shrub species are those most commonly used by practitioners of topiary
Box (Buxus sempervirens)
Also known as common box or boxwood, this small tree has long been considered the gold standard for topiary-suitable species, and it's not difficult to see why. It's leaves are small and vibrantly green, and grow densely enough to almost completely obscure the branches of healthy plants. Despite this dense, energy-intensive growth, the plant is remarkably hardy and will tolerate close and repeated shearings and prunings for many years. Another advantage of using box is the unusual manner in which it flowers - its flowers, despite relying on insect pollination, have no petals to break up the uniform greenery in flowering season, instead relying on the strong scent they produce.
However, box is not the perfect topiary tree - in fact, some budding landscapers may suddenly find them intolerable to work with when summer hits. The aforementioned scent produced by the box can become overpoweringly strong and cloying in summer, and even in winter the distinctive fragrance is far from universally liked. The chemical that produces this scent can also, in rare cases, provoke allergenic responses and skin irritation in some people. Box also has a an extremely dense and slow-growing wood, so plants bought as small shrubs can take years or even decades to grow to the size you desire.
Privet (Ligustrum jonandrum)
The term 'privet' is commonly used to refer to any of the many species that make up the privet family of trees and shrubs, but Ligustrum jonandrum is the species generally favoured for topiary. A densely-leafed, fast growing plant, this privet is also extraordinarily tolerant of shearing, making it an ideal starter plant for the novice topiarist. If you don't have your set on year round uniformity, you will also appreciate the small, delicate white flowers that appear in late summer.
However, privets have a number of drawbacks, chief among which is confusion over which species of privet is which. When purchasing a privet plant you should also go by the Latin name, as other varieties of privet are far less suitable for topiary - some are even considered invasive weeds in Australia, and cultivation is banned in certain areas. Privets are also high allergenic plants, and can cause skin rashes and respiratory problems in people vulnerable to its pollen. The berries it produces are also mildly toxic, making it an unsuitable choice for families with young children
Holly (Ilex aquifolium)
Don't worry - you aren't expected to get up close and personal with the savage spikes of ordinary holly leaves. Holly cultivars sold for topiary have generally been selectively bred to produce smoother, rounder leaves, although the distinctive and attractive red berries will still appear in winter. The great advantage of these shrubs is that they can endure shade, dehydration and poor soil quality, making them ideal choices for areas with high soil salinity or acidity. They are also hardy enough to endure regular shearing, and the wood is both strong and flexible, ensuring that your topiary will survive almost any storm.
However, holly hails from much cooler parts of the world, and a holly topiary left to stand in the baking heat of an Australian summer will not last long - as such, they can be somewhat difficult to find unless you go to a topiary specialist. These plants are much more suitable for shady areas, such as porches and alongside walls. You will also need at least two plants if you prize those red berries, as holly plants are monosexual and must be pollinated by a plant of the opposite sex to bear fruit.