Evergreen shrubs yellowing
I have (4) of these shrubs. (3) are doing very well. This particular one is thinning out and yellowing:
It's about 2 feet away from another evergreen shrub/tree (sorry don't know the type, but here's the pic):
The yellowing shrub has been in the ground for about 10 years now and just started this a year or so ago. Wondering if the close proximity to the other shrub is causing a moisture issue, crowded out, etc? Don't see where there's any insect problem. Is this possibly an iron issue? Hate to lost this one. Any help is appreciated! Sorry the pics are that large!