This article arose because of a problem in my day job, as head gardener of Lincoln’s Inn in London. Having been watching for years for the dreaded box blight to start affecting our hedges, it was actually another little blighter that arrived instead this year. We suffered a bad outbreak of box tree moth, which defoliated most of our topiary. At first it was a little webbing, then distinctive green caterpillars and mountains of frass. I sprayed with professional chemicals but was unable to spray the small parterre hedge around the herb garden in case of drift.
Other gardening friends in London tell me they have already been dealing with this pest for a few years and it is seriously taking hold now. The moth was first found in traps in the UK in 2008 and what started out as a few sightings in private Home Counties gardens rose to more than 800 sightings in 2015-16. It looks likely to become a serious problem, and one that could be a horrible threat to British gardens known for their topiary.
So what to do? In my garden, as others will have experienced, I have two options — keep spraying at regular intervals (but that is not possible across the whole site, where they are growing next to edibles) or rip out the box and replace it with another low hedge.
If the latter, what is a good alternative to box? There are several on the market but they all have
their strengths and weaknesses too. The three most often suggested are the Japanese holly (Ilex crenata), especially the kanehirae variety; box honeysuckle (Lonicera nitida Maygreen — as its name suggests, a strong mid-green hedge that can be closely clipped); and Euonymus japonicus ‘Jean Hugues’, which has such a strong waxy growth that it can actually be mistaken for fake box.
Ilex crenata - image: Floramedia
While the Ilex and the Euonymus have more aesthetic appeal than Lonicera, they have their issues —
as pointed out by our professional growers. The Ilex can be a little fussy with soil and can get yellowing leaves or have them drop without apparent cause. They are also both more expensive because they cannot be bought bare root.
Other options are more unusual.
I have seen lovely low hedges of purple Berberis growing at Penshurst Place in Kent, edging formal beds. At Middle Temple, head gardener Kate Jenrick tends to a neat hedge of Teucrium fruticans, which has a lovely airy look, with its sparse silvery leaves and lilac-blue flowers. Teucrium × lucidrys, with greener leaves, creates a much lower hedge and was historically used as knot garden edging.
The Berberis and Teucrium are my current favourites but there are plenty of others — the RHS has great online information on hedge selection. The well-known hedges are represented, such as lavenders ‘Hidcote’ Award of Garden Merit (AGM) and ‘Munstead’, but there are also lesser-known choices such as Hebe × franciscana ‘Blue Gem’, Olearia × haastii and Santolina chamaecyparissus ‘Nana’ AGM.
With such a range of genera and varieties available, it is difficult to give general cultivation notes for growing low hedges. Obviously, thinking about the kind of hedge you want first is important — evergreen, deciduous, flowering, formal or informal. Then consider maintenance. Evergreens are ideally clipped twice a year and deciduous once in late summer.
When buying in bulk it is best to get field-grown material, supplied bare root, because it will be far cheaper. Not all varieties suit this and some prefer being pot-grown. Planting small whips, about 60cm tall, means you are more likely to get your hedge established because they have not been cosseted and will grow into the space.
For those growing box and wishing to continue to do so, there are ways to control box tree moth. Careful picking off of caterpillars can be effective if done every two-to-three days. Pheromone traps can be used to catch the males and prevent fertilisation. Larger plants can be hosed down with a strong jet of water. Contact insecticides such as Decis or Toppel are very effective but they need careful handling.
Biopesticides that attack the caterpillars are less harmful to the wider environment.
Teucrium × lucidrys - image: Floramedia
What the specialists say
Will Bodsworth, director, Hedging Plants Direct, Essex
"We are now stocking Euonymus japonicus ‘Jean Hugues’, which is more upright than box and the leaf is very waxy, making it a good strong plant. We also stock Ilex kanehirae. The leaf is less waxy than ‘Jean Hugues’, making it softer in appearance.
"Another old favourite that has been used in supermarket car parks, mainly due to the low cost, is Lonicera nitida Maygreen. This plant clips very well into small hedges and it also self-roots, which can be helpful. However, it suffers with going woody in time.
"The main problem with ‘Jean Hugues’ and kanehirae isn’t a plant problem, it’s a production problem. These plants are only really available pot-grown or root balled. They don’t transplant from bare root, making the initial cost higher than box and Lonicera, which puts off a lot of people who are installing a new hedge at around 20-50cm high.
"Buxus prefers soil over compost. Box always thrives when grown bare root in a low-cost field environment rather than pot-grown in a high-cost greenhouse. The opposite can be said for the substitutes."
Sam James, marketing executive, Hedges Direct, Lancashire
"We can recommend a couple of viable alternatives to use in place of box. Ilex crenata is ideal. It has small, dark-green glossy leaves and is very similar in look to box hedging. The advantages are that it is resistant to box blight but also to leaf scorch, which can occur with some hedges on pruning. Ilex crenata also regenerates fairly easily from old wood, allowing it to be reshaped even if neglected over time. It can be used as a small hedge, border edge and can also be shaped into topiary. It is more hardy than box, meaning it will tolerate colder conditions, allowing it to be grown successfully in more locations in the UK.
"Euonymus japonicus ‘Jean Hugues’ has been tipped as the hedging plant most likely to replace box as the favourite option for low hedging and borders. It is resistant to blight and is evergreen — perfect for parterres and formal hedging. It is also exceptionally hardy and will grow in pretty much every type of soil, making it a real all-rounder."
Lonicera nitida ‘Elegant’ - image: Floramedia
Chris Day, garden centre publicity manager, Buckingham Nurseries & Garden Centre, near Milton Keynes
"Box blight has certainly hit public confidence of all Buxus, although from our experience over the years
it tends to be dwarf box (Buxus sempervirens ‘Suffruticosa’) which is more prone to the disease and that suffers badly.
"We have been actively promoting the use of alternatives such as hedge germander (Teucrium × lucidrys), evergreen honeysuckle (Lonicera nitida ‘Elegant’), the euonymus gold (‘Emerald ‘n’ Gold) and silver (‘Emerald Gaiety’) and box-leaved holly (Ilex crenata Dark Green).
Both the varieties of lavender — ‘Munstead’ and ‘Hidcote’ — are also popular, especially if flower and fragrance are required.
"While everything would suggest that Ilex crenata should be a perfect hedging plant, we’ve discovered it can be quite fickle to the types of soil it requires and there can be issues of yellowing foliage as well as leaf fall. This appears to happen to perfectly healthy plants for no obvious reason. Not only is this frustrating for our customers, the inconsistencies of growing this plant cause some concern, hence a slight reluctance to promote it more directly here."
Lavandula angustifolia ‘Munstead’- image: Floramedia
Species and varieties
Good alternatives to box
Euonymus japonicus ‘Jean Hugues’ is a lovely compact shrub with dense evergreen foliage and it has been tipped as the hedging plant most likely to replace box as the favourite option for low hedging and borders.
It is hardy and will grow in pretty much every type of soil. Slow-growing and easy to prune and maintain. Height: up to 1m.
Ilex crenata, or Japanese holly, is a hardy evergreen with small, dark-green glossy leaves. It can be used as a small hedge and border edge as well as being shaped into topiary. Regenerates from old wood and is not susceptible to leaf scorch, but leaves can sometimes suffer from yellowing or fall off without apparent cause.
Ilex kanehirae is a fast-growing plant that is very similar in appearance to box, with small, dense leaves. It is a closer match to box than Ilex crenata. Height (if allowed): 2.5m.
Lonicera nitida Maygreen (syn. ‘Maigrün’) is a close-knit, bushy evergreen hedging plant that has a leaf very similar to box, though they are borne on arching stems. Being very tolerant to hard pruning and clipping, it is often used for topiary. Height: up to 2m.
Other low hedges
Euonymus fortunei ‘Emerald ‘n’ Gold’ AGM (H5) is a dwarf evergreen with bright variegated green and gold foliage. Tolerant of dense shade. Height: 60cm.
E. fortunei ‘Emerald Gaiety’ AGM (H5) is a dwarf evergreen plant with bright variegated green and silver foliage. Tolerant of dense shade. Height: 1m.
Lavandula angustifolia ‘Munstead’ has greyish-green, slender, aromatic, evergreen foliage along with dense spikes of fragrant, bluish-purple flowers all summer.
Lavandula angustifolia ‘Hidcote’ AGM (H5) is a good variety for a low hedge, with silvery-grey narrow leaves and violet flower spikes from July to September.
Lonicera nitida ‘Elegant’ is a hedge-forming honeysuckle. A fast-growing evergreen plant with tiny leaves, making it a good, dense hedge when trimmed. Shade-tolerant but not suitable for very cold positions.
Teucrium × lucidrys, or hedge germander, is a fully hardy evergreen that makes a low, neat, flowering hedge. It has small, lobed dark-green leaves that have a spicy aroma, as well as clusters of small rose-pink flowers in mid-to-late summer. Height: 30cm.
Thank you to Floramedia, which supplied the images for this article from its photo library www.floramedia-picture-library.com