Friday, 5 May 2017

Why you don't need to worry about box blight in your garden

Green fingered blogGardeners, especially anyone with a classical or formal garden or planting scheme, have become steadily more disheartened in recent years by the spread of box blight. Box is growing strongly at the moment, and from June onwards is the time to clip it back into shape, so if there are problems, you are likely to notice them soon, if you haven't already. Box blight can do tremendous damage, but you don't need to worry, because there are things you can do, and if all else fails there are alternatives to box which you can use to give your garden the same look.  

Buxus sempervirens is incredibly useful in the garden. It can be trained and clipped easily to any shape. It grows relatively slowly so is low maintenance (depending how elaborate a shape you are training it into), usually needing clipping just a couple of times a year. It is a perfect foil for almost any planting scheme, providing a bright green backdrop or edge to borders that offsets almost anything you put in front of or behind it. It's evergreen so provides structure in winter, and it adds a touch of class, being associated often with grand parterres in some of the most famous gardens in the world such as Villa Lante in Italy or Chateau Villandry in France.  
 
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Box blight causes die back and leaves bare patches
Those of us who've been inspired by such places and used box in our gardens have noted the advance of blight in recent years. It's a fungal disease, causing leaves to drop off and creating bare patches. An affected box hedge looks the opposite of the neatly clipped shape it is intended to be. It looks a mess. Controlling box blight is difficult - it's hard to avoid the fungal spores spreading. To be without box in the garden altogether would be a terrible shame.
 
So what can we do about it?
 
Prevention
Whilst it is difficult to prevent blight spreading, you can reduce the risk by ensuring there is plenty of air circulation around the plants. Though box enjoys moisture around its roots, excessive moisture around the leaves will work in favour of the fungus. Be careful to clip and prune box when it's dry and forecast to stay so for a few days. Moisture in the cut ends of leaves is also more likely to become infected and develop problems. Good hygiene is important too. If you are dealing with affected plants, avoid touching others until you've washed your hands, and leaves and stems that are removed need to be carefully burned or thrown away, not composted.
 
Treatment
Despite maintaining good airflow around them and clipping them at the right time, your box plants may still be affected. No-one is immune. If so, all you can really do is cut out the affected parts, and follow the advice above to create a suitable environment in the hope that eventually the box will re-grow. This is perfectly possible given the right conditions, but may take some time. There are fungicides aimed at controlling box blight, but no conclusive proof of how effective they are yet.
 
Alternatives
If you are not prepared to wait, risk it, or you've tried everything and decided box is no longer worth the effort, there are other plants you can use in its place. None of them do all the things box can do as well as box does, but they are all useful in different ways.

Euonymus
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Low formal hedging with euonymus at Hidcote
There are several small leaved varieties of euonymus that can be used to form a low growing hedge as in this example at Hidcote. Most available forms are variegated so have a different look to box, but are also evergreen and certainly provide a similar structure. There are several colour combinations available such as "Emerald & Gold", "Emerald Gaiety" and "Golden Prince", each with different coloured leaves and leaf edges. Or try Euonymus japonica microphyllus which has fairly small leaves too. Euonymus tends to spread much more than box so needs more pruning to maintain the desired shape.  

Ilex Crenata
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This small leaved holly is tough, hardy and looks very similar to box with small dark green glossy leaves. It can be clipped into a variety of shapes, and grows slowly so doesn't need much work to look after it. In my view it's lovely to look at and a great substitute for box, though I don't think it's quite as easy to clip into such tight shapes as box is, so your ilex crenata topiary might look just a bit fluffy  round the edges.



Santolina
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Santolina can be clipped into cloud shapes
Santolina, known as Cotton Lavender, is a worthwhile addition to your garden in its own right, with soft silver foliage that has a delightful scent to it, and a slightly Mediterranean feel. If you let it grow it will produce yellow flowers on long stems, and eventually will get leggy and woody like lavender, but if you keep clipping it you can keep it to a compact bushy shape to match box, as you can see from this picture where it was opposite the box. Note the past tense - it is not in that spot any more because it didn't survive the wet winters we have here in Cardiff, but if you have drier conditions, or can protect it in winter (which is what I have done since with a subsequent planting elsewhere) it makes an excellent low hedge or cloud shape.

Hebe sutherlandii
Green fingered blogThis variety of Hebe in particular, seen here providing winter structure, can be clipped into really tight compact balls to give a very similar effect to box. Other hebe varieties can be used in similar ways but have a tendency to get leggy if left completely to their own devices. Sutherlandii is much less prone to do this and is by far the best I have found for this particular role. A lighter, bluer green colour, hardy, and does keep the shape you give it for quite a while.
Lonicera Nitida
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Large ball of lonicera nitida
This is my personal favourite replacement for box. I have read that other people think it grows too quickly and gets out of control. Certainly it needs more regular clipping than the others I've suggested, but nothing problematic in my view. And you can cut it back quite hard without spoiling it anyway. Particularly flexible, Lonicera nitida can be used for low hedging, or any form of topiary. I've used it for large and small ball or dome shapes, as well as flat topped squares with other plants growing through it. It has smaller leaves than box so can potentially form even tighter and more compact shapes. Like all the box alternatives listed, it is less sensitive than box, so can be clipped almost any time, regardless of temperature or time of year.
 
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Lonicera nitida clipped to a flat square shape
So there you have my 5 alternatives to Buxus sempervirens, should you need them, or fancy including some in your garden as insurance against your box being affected by blight in the future (literally hedging your bets!). If you have any others, please let me know via the comments box, twitter, or my facebook page. It would be good to hear any other ways of overcoming box blight, so do get in touch. 

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