Boxwood (Buxus) leaves look funny

midwestbonsai

On some of the leaves on my boxwood are looking a little funny. With brown spots or sploches.
This will be the first winter with it, could it be caused by the lowering temps, or should I worry?

I do not know the variety of this tree, can any one tell from the leaves? its either japanese or english.

1. front of some leaves
2. back of a leaf

-Paul

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ALDEVAUX

The symptoms of the leaf spots do not look like those of Macrophoma which is about the only major leaf spot reported on boxwood.

However, leaf spots on plants are not only due to parasitic infections but also by physiological (abiotic) or non parasitic factors. The causing agent of those spots are not always easy to identify because there can be a dozen, or combination, of them that can be implied to cause various types of symptoms on leaves.

It can go from stresses due to temperature, water, light, nutrition, pollution etc. on the plants. This is why we need to know a sort of history of what the plant has gone through to be able to tell which factor or factors could be responsable for the visible symptoms shown on the leaves.

It is always easier to diagnose a disease if we know how the spots are distributed over the foliage : are they only on the older leaves ?, Do the twigs also have spots? Are the spots only on one side of the plant? etc....

From the shape of the spots your picture shows and their distribution over the leaf surface which seems to be mostly between the veins, I would think that is it is a physiological stress as I explained above and I don't think they are very important.

midwestbonsai

Well lets see. . .
the spots are on the older leaves all over the tree, but not on all of the older leaves.
Not on the twigs.
This tree has been in the same spot all year, getting lots of sun and proper watering I think. Water when the soil is dry.
One thing I noticed is that it has not grown very much this year.
Thanks Aldevaux, hope this helps you some.

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ALDEVAUX

Sorry midwestbonsai, for my late answer, my computer was out of order yesterday.
As I said before, it is very difficult to diagnose most physiological diseases of plants. Howerver, in your case, since the spots are confined to mostly the older leaves and all over the plant, it means that the stress happened some time ago and should be over since the younger leaves are not affected.
Also, since the plant has not grown very much this season, it has probably a nutritional (too much or too little fertiliser ?) problem or a soil problem (pH, compaction etc,.) which stresses it.
The best solution would be to repot the plant as soon as it is possible to do so and change the soil. Good luck.