Forget Ilex crenata: this is the best alternative to box
Matthew Pottage, Curator at RHS Garden Wisley, believes he has found a worthy alternative to box – and it's not the widely hailed Ilex crenata
For several years now, our beloved box balls, hedges and topiary have faced a twin threat: box blight, and box tree caterpillar. Box blight is a fungal disease that causes brown leaves, straw-coloured bare patches and dieback, and box tree caterpillar can defoliate a plant in a matter of days.
Both problems can be kept under control by keeping a very close eye on your plants, by taking preventive measures and acting as soon as you see signs of attack. But in the case of box caterpillar especially, it can involve spraying with a biological control, Bacillus thuringiensis, several times a year (the caterpillars are active from March to October), which quickly becomes tiresome if you have a lot of box in your garden. And if an outbreak happens to coincide with your summer holiday, it may be too late to save your plants when you get back.
Watch a clip of RHS Wisley's alternative hedging plants
Most garden designers now choose not to add box plants to new planting schemes, and while garden centres still sell box to the unsuspecting public, many gardeners would now avoid planting it. But what to plant as an alternative? Tolerant of close clipping, suited to both sunny spots and shade, and evergreen, box is hard to beat.
Until now, Ilex crenata (Japanese holly) was hailed by many as the best alternative. Slow growing and compact, it is particularly suited to shaping and cloud pruning. However, Matthew Pottage, who is overseeing a trial of clippable, small-leaved evergreen shrubs to box at RHS Garden Wisley, says: 'Ilex crenata seemed to be the solution to everyone's prayers. But in the Wisley climate (hot and dry in the summer, on sandy soil), it appeared to die slowly, going uncontrollably yellow across its foliage."
Matthew says his preferred alternative is a conifer, Podocarpus. 'For the purist wishing to replace the box-like, matt-green, small leaves with similar, the superb Podocarpus nivalis could well save the day. It isn't too fast growing, is easy to propagate, and can regenerate from old wood. It can cope with full sun to part shade."
Matthew also rates colourful podocarp cultivars: Podocarpus 'Chocolate Box' flushes a magnificent bronze in autumn, while Podocarpus totara 'Aureus' flushes mustard-yellow in the colder months. Podocarpus is not yet widely available, with only a handful of suppliers, but it is easy to propagate from semi-ripe cuttings.
Matthew also urges gardeners to (ahem) think out of the box when choosing a box alternative, opting for plants that may be variegated, or with different colours or forms. 'Perhaps the long-held snobbery around plants with coloured and variegated leaves will start to subside if their qualities for other garden uses come into play."
Matthew has plenty of other recommendations for box alternatives too, including several yew cultivars, pittosporum, berberis and Corokia. Read about Matthew's 13 recommendations for alternatives to box.
Veronica Peerless is a trained horticulturalist and garden designer.