By Milliemills
Carmarthenshire,
United Kingdom 
I have a number of box plants where the leaves have turned orange almost autumnal looking but not in a nice way - I don't think it's box blight because the stems are not stripped of leaves.... perhaps a deficiency in something. I have sprayed the leaves with diluted liqued seaweed and fed the roots with fish blood and bone but haven't seen any benefits yet..... grateful for any comments.
9 Sep, 2011
Answers
Hi Bamboo - I've had the plants for about 3 years and some are in the ground in a woodland setting and some are in pots......
9 Sep, 2011
I read that the commonest causes of this are boxwood decline disease and too much sun. Since the latter isn't likely to be appropriate, I wondered about the former, but boxwood decline disease usually only affects plants over 20 years old. The other cause is worse - phytopthera and other fungal disease. Might be worth treating the plants with a fungicide to see if it helps, but if its phytopthera, that lives in the soil and attacks from the roots upwards usually.
9 Sep, 2011
Some of mine have gone a similar orange colour. I think it is due to lack of water and compacted soil that is causing it in mone. Am planning on fixing both in a few weeks time.
9 Sep, 2011
Thanks all - I'm now hoping that Kildermorie is right because the alternative sounds fatal! Lack of water and compacted soil would both apply because I have the box plants planted around the edge of a lawn so perhaps they are competing with the grass for water ... I have about 30 of them so the thought of having to water more regularly isn't pleasing but thanks for your comments.
9 Sep, 2011
How long have you had the plants and are they in the ground or in pots?
9 Sep, 2011