How to prune box and yew

Box and Yew have long been used to add formality to gardens as hedges or topiary.

Either way, they need regular pruning to keep their shape. Use sharp and clean hedge cutters or shears, especially when pruning Box, as damage makes the plants more susceptible to box blight. It’s also advisable to disinfect tools after pruning. Here’s how to prune your Box and Yew like a pro…

How to prune box and yew hedges

Box can be pruned to form tight hedges or glorious shapes
Image: Box Hedging from Thompson & Morgan

If you’re pruning a hedge, always take the time to string a line to ensure a level and straight finish. You should also check for nesting birds before you begin as it’s illegal to disturb them. If your hedge is tall, get yourself a sturdy set of steps so you can tackle the job safely. 

Large, formal hedges should be cut with a slight taper towards the top. This allows more light to get to the bottom of the hedge. Lower hedges, such as in a parterre, should have vertical sides. Either way, do keep stepping back and checking as you clip – it’s all too easy to cut off too much.

If you need to rejuvenate an overgrown hedge, both box and yew can be cut back hard in late spring. In the case of yew hedges, this is best done gradually. Cut back one side and allow it to regrow before tackling the other side.

When is the best time to prune Box hedges?

Prune Box twice a year - in May and September
Image: Thompson & Morgan

Prune box (Buxus) in late May or early June after all risk of frost has passed. It can then be tidied up in September to ensure a crisp finish over winter.

Choose a dry but cloudy day to tackle your hedge or trim your topiary. Avoid pruning in hot sunshine as this can lead to leaf scorch, while damp, humid conditions encourage the spread of box blight.

Remove all the clippings immediately to discourage the spread of blight. If you put down some plastic before you start work, it’s easier to whisk them away when you’re done. 

When is the best time to prune Yew hedges?

Prune Yew hedges from August to October
Image: English Yew Hedging from Thompson & Morgan

Yew (Taxus baccata) can be kept in shape with an annual trim, best done between August and October. 

Yew can grow up to 12 inches in a season. If you want a thick, dense hedge, don’t trim the ‘leader’ until it reaches the height you require. Trimming the side shoots, however, will encourage bushier growth and stimulate the hedge to thicken up as it grows. 

How to trim topiary shapes

Regularly trim your topiary to keep your chosen style looking neat
Image: Thompson & Morgan

Topiary shapes such as balls, spirals or more creative freestyle masterpieces are also best achieved with a guide – bamboo canes are ideal for providing a straight vertical line. Use shears to create the shape, and sharp secateurs to finish the finer details. Trim in May, July and September to maintain a tight, neat shape. 

Love the idea of having more formal and topiary hedging plants to trim and prune? Check out our great selection of shrubs for manicured boundaries, topiary structures and impressive hedges. Find conifers growing advice & expert gardening tips at our hub page.