About three weeks some leaves on two small bushes begin to turn brown on top and side. Did not appear to be unusual; within the last week and a half there has been a substantial spreading of the brownish/dead leaves. There is no evidence of exterior insect damage or infestation. The name of the bush is unknown, although it may be a type of boxwood. It's about 3' high and about 3' wide; possibility 7 - 10 years old; located in a mostly sunny area with good drainage. Your recommendations/suggestions will be appreciated.
This is a Japanese holly. You can tell by the "teeth" on the leaves.
It's impossible for us to say what has caused the dieback. Some possibilities include:
- tight foliage (result of shearing) which does not allow air circulation and fast drying of foliage after rains/watering
- overhead watering
- too much mulch (never pile or allow to touch the trunk of trees or shrubs)
- planted too deeply
- drought (much of Maryland has had drought conditions since June)
You should prune out dead branches and you might consider letting the branches grow into a more natural shape that allows better air circulation.
Here is a helpful fact sheet with some lesser known causes of problems: http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG86%20Common%20Abio...