I have to admit it, I love formal gardens, those with a definite structure, sense of purpose and everything in its place, writes Hannah Stephenson.

Clipped box hedges, strong geometry using evergreens shaped carefully into balls and pyramids, evenly spaced in uniform lines or sections, can give a garden - front or back - a contemporary lift. Even a couple of box balls or standard bays in pots either side of your front door can give your home a grand entrance feel.

If you want to add some formality to your patio this summer as a backdrop or accompaniment to pots which are full of colourful blooms, topiary may be the answer.

Potted topiary can add emphasis to a garden design, for example, placing uniformly clipped globes along the edge of a path. Shaped plants are often used in formal settings but can also act as valuable exclamation marks in more informal schemes.

Among the plants easiest to shape to your requirements are box (Buxus sempervirens), sweet bay (Laurus nobilis), yew (Taxus baccata) and privet (Ligustrum delavayanum).

While slow-growing evergreens are the traditional topiary plants, you can use climbers to cover wire frames for a faster result.

So, where do you start if you want to have a go?

Beginners should start with a simple box ball or bay pyramid that has already been trained to shape and keep it that way by trimming it twice a year, in early summer and early autumn. Potted topiary also needs to be watered well in summer and protected from frost in winter, so it's best to place it near the house.

As your topiary grows, clip it very lightly every couple of months, taking off the tips of the shoots, to keep its natural shape while it grows and encourage branching, which will help thicken the shape.

Tools you will need are secateurs, small hand shears or one-handed 'sheep' shears. Secateurs should be used to shape larger-leaved plants including bay, holly and viburnum.

If you are trimming a ball or dome, stand above the plant, turning the shears upside down so that the shape of the blade follows the curve. Keep walking around and standing back to view the shape, making sure everything is even.

Most topiary is based around a wire framework. Young shoots are tied into the frame to create bushy growth, then sideshoots are tied into the framework and cut back regularly to maintain the shape.

If you have a little more time to create your own pyramid in a pot, choose a plant which looks like it will grow to roughly the right shape, plant it in the pot and place three bamboo canes made into a wigwam shape around it, tied with twine at the top. Tie any long shoots to the cane with twine to form the outer edges, then prune the plants to the 'pyramid' template to maintain the shape.

You should avoid shaping evergreens between the end of summer and mid to late spring, or the soft re-growth might not survive frosts.

For a quick fix, grow some plain green ivy over a wire topiary frame to create a traditional effect much quicker. Just plant the ivy around the rim of the pot and twine the trails around the wires of the frame. The leaves should hold the stems in place and you can snip off unwanted shoots once your frame is covered.

Suitable ivy with short joints includes Hedera helix 'Duckfoot' and 'Tres Coupe', which remain compact.

Remember that potted topiary can also be slotted into your flower border at any time of year to fill gaps and add interest, although in winter more elaborate shapes you may have created out of bent wire, from peacocks to teddy bears, will be a good talking point when there's nothing else on the patio.