Ever wondered how to shape your evergreens? Experts share their tips

Independent

5 days ago

Topiary offers a unique way for plants to shape our gardens.
Shaping plants into balls, pyramids and even birds doesn't have to be as complicated as it might seem, so you don't just have to admire topiary in the gardens of stately homes and horticultural shows.
A new photographic exhibition, On The Hedge, opening at RHS Garden Wisley in Surrey, charts our relationship with hedges and topiary, from their role in shaping our landscapes and homes, to their environmental benefits.
'From a design point of view, topiary is really important, even if it's just a simple basic structure. A cube, or a cone, or even just a ball of some sort gives really good structure through the winter when a lot of gardens go quiet,' says RHS horticultural advisor, Nick Turrell.
'If your shape – it could be a simple cone or a cube – is repeated through a garden, the eye will immediately pick up on that repetition. In summer, it might just sit in the background but it still provides an important structural framework.
'Then in the winter it looks amazing because the frost sits on it.'
Can you have topiary in a smaller gardens?
'Yes – it could be knee high, a cube or a dome and you could grow them in a border, like an exclamation mark among all the froth of the flowers. I've done it even in tiny little postage stamp-sized gardens, when you have two or three in the border which adds a good bit of solidity,' says Turrell.
If you've only got room for a pot, put your evergreen in as big a pot as you can, which won't dry out as quickly as smaller containers, but be aware that it will require more TLC than if you plant it in a border, he advises.
'It will require a bit more attention. Any plant, whether it's clipped or not, is totally dependent on you for food and water. It will need feeding through the summer, ideally every three weeks.
'After the first season the potting compost will have run out of nutrients so it's down to you to feed it.'
If the compost needs changing, the chances are you'll need to repot your topiary into a bigger pot. If you don't have room for that, it will need regular feeding and will benefit from mulching with some well-rotted manure in the autumn, he suggests.
What are the best plants for topiary?
Box blight and box tree caterpillar are still a real problem, so find an alternative, he suggests.
His top three choices are yew, small-leaved privet and Wilson's honeysuckle (Lonicera nitida).
'With yew, you can have it whatever size you like, it always comes back and it has tiny needles, which lends itself to close clipping.'
The small-leaved privet doesn't grow too tall – reaching around 1.5m if you let it – and is quite happy to be clipped, he says.
Wilson's honeysuckle is strong-growing, with tiny leaves. You can grow it in a pot and if you occasionally forget to water it, it can bounce back, he says.
Look at the size of the leaves of whichever plant you choose, because the bigger the leaf the worse it is to topiarise, he adds.
'You can end up cutting through a broad leaf halfway through when you are clipping it and then the ends can start fraying and going a bit brown, which doesn't look good.'
Only buy one plant for each shape
Don't plant, for instance, three of the same species next to each other hoping that they will be dense enough to give you a shape more quickly, because they will eventually end up fighting for space and light, he advises.
'If you're looking for a cone or a ball which is say, a metre high, you can buy them ready-made but they are expensive. If you buy a yew just as a plant, which is 60cm tall, it won't cost as much and as long as you are patient and feed and water it you can start trimming it once it reaches the size you want it to be.
'They will grow fairly quickly. Within 18 months – two seasons – you should start to see the beginnings of the shape, if it's not too intricate, like a cockerel.'
'Keep it simple. A good pair of sharp shears or even some little handheld long-nosed snips are perfect. Don't worry about electric hedge trimmers – it's the difference between using an electric shaver and a razor blade. You get a much better finish with a sharp pair of shears or long-nosed snips.
'Using those tools also encourages you to look carefully at what you are doing, whereas electric hedging shears are a bit slapdash.'
Put a frame over the plant – you can buy shaped frames at garden centres and topiary specialists. Anything that grows outside the frame can be clipped to get the shape you want.
Position the frame over the top of the plant after you've planted it. They are like a plant support. Once the plant has grown and you have achieved your desired shape, you can remove the frame, or leave it in place as a marker, especially if it is an intricate shape, he suggests.
Beginners might start with easy cones or cubes, but you can progress to cloud shapes, birds and animals.
There's no hard and fast rule about when to trim but it would normally be in spring or autumn, depending on how fast it grows, he says.
Step back every few snips when you are trimming, to check on the shape and the perspective.
'If you cut off too much in one section, you'll probably need to cut the whole lot down to that size,' he suggests. 'It's not the end of the world, it just delays the ultimate size that you want.'
If you buy a plant which is already shaped, take a picture of it at the outset, so that if it starts growing fast, you can see what shape it looked like at the start.
If you want your topiary to inhabit your flower borders, don't be afraid of planting your colour close to the topiary, which will create a contrast between a crisp, shaped evergreen and a froth of flowers, he says.
If you want your topiary to be a stand-alone showstopper in, say, a lawn, don't plant anything nearby which will take away its prima donna status, he suggests.