Ashridge Nurseries Blog & Recipes

Were you a Derby Day loser?

We get a few enquiries about box blight from customers (and non-customers) who are worried that their box hedging might have contracted the dread disease.

When we are sent samples only about a quarter prove to be suffering from box blight which probably means that it is not as serious as people think - more "scare" than "there". Where it is box blight, almost invariably the gardener concerned followed the old saw about never clipping your box hedge before Derby Day.

A lot of work has been going on researching the causes, treatments and outcomes of box blight.  We know that it is caused by two fungal organisms working in concert, that it spreads by infecting cuts on leaves and stems and that it is most likely to do so in warm, damp weather.

A lot flows from that:
1. Clip your box hedges so that the tops are NOT flat. Make them domed or pointed as this stops water resting in the leaves and creating a moist microclimate for fungal infections.

2. Try to clip them when it is COLD. At Highgrove, they have had good results clipping their box at.....  Christmas. When it is cold and blight is sensibly sleeping. (It is at its most active in May-August, so it makes sense to clip outside these months if you can).

3. Spray your box hedging to prevent an outbreak.  Alternate copper fungicide and Scotts Roseclear3 and spray to 2-3 sprays a season.

4. We think box "grows out" of blight. There is a lot of evidence to that effect, but it needs to lose a lot of top growth first.  The good news is that it will probably survive if you get blight.  The bad news is that box hedging grows so slowly that if you have blight in an established hedge it is going to look pretty grotty for quite a while.

6 thoughts on “Were you a Derby Day loser?”

  • Richard

    We have bought some buxus sempervirens from you before, so I am hoping that you may be able to help with a problem that I have in my exsisting box hedges. These were planted some 8 years ago and this year the tops some of our box hedging has suddenly and rapidly died off, the dying off spreading along the top surface of the hedge, moving down thro the plant but leaving the outside edges still alive and green. The leaves go a light brown and die, no sign of spots or mildew on the leaves. At first I thought that the problem was as a result of some liquid being poured onto the plants but the speed with which it seems to be spreading is rather alarming. I have tried local experts but no answers so far.

    Have you any ideas ? I have heard about box blight, could it be this ? Is there a solution to blight ? I understand that you are not really in the market of plant disease and treatment but I can't think of anyone else to ask. Any ideas?
    Thankyou for any help you can give,
    Richard Hazard ( groundsman - Inn on the Lake)

  • julian

    Without seeing a sample this is tough, but our guess would be box blight. Please send us a sample if you want. One of the symptoms of box blight is a dark brown/black streaking that tends to run vertically up and down the stems.

    Can't do much more than repeat what I said above:

    1. Clip your box hedge plants so that the tops are NOT flat. Make them curved or shaped to prevent rainwater and dew resting in the foliage and creating an environment that encourages fungal infections.
    2. Clip them in WINTER. At Highgrove box hedging is clipped at Christmas.....
    3. Spray your box hedging ASAP. To begin use copper fungicide and then apply Scotts Roseclear3 2-3 weeks later. Repeat the alternation while you have a problem. When the problem is gone reduce this to 2-3 applications a season.
    4. Box can fight blight off. There is a lot of evidence supporting this, but it you will lose a lot of growth first. If you have blight your 8 year old hedge is going to look a bit threadbare for a while - you may have to brace yourseld and take it out if it is really strategic.....

  • Richard Hazard

    Thanks for your reply. I have started by spraying the box with Roseclear 3 and the copper fungicide in 2 weeks. I'll certainly experiment with clipping our box hedges during the colder months and try not to leave a flat surface tho' this is the traditional shape of the hedge that is required. Up here we have had a very wet July and August even by our standards so the conditions for the spread of fungal infections have been perfect, I hope the plants have the ability to grow out of the problem with teatment because the effected areas are on a set of steps used for wedding photos, centre stage so to say, so I'll see how things work out.
    Thankyou for your help
    Richard Hazard.

  • Greg Cumming

    We have some of the symptoms of blight but not all. The outside of the hedges look poor as well. These hedges are of the small box variety and so are only about 30cm high and have been there for about 5 years. They are in very chalky soil. Could this be a problem? Should we be feeding them with some kind of acidic solution?

    Any ideas would be gratefully received.


  • I have symptoms with two box cone shape trees they are about 8-10 years old,two foot tall, there leaves started to go yellow/brown in the centre of the bush then fall off i first thought it was over watering or lack of water as they are in there own walled garden, i then noticed lots of baby snails in the box thought it may be, they were the cause, as time has gone on the trees are no better starting to look thin loosing lots of leaves outside is still green,after reading Richards symptoms Sep 2009 they are much the same as mine, do you think my box has blight????? .Evelyn

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