I live in Central Florida. I have boxwoods around my patio that have probably been there 25 or more years. This year I've noticed that some of them are in decline, and some branches have actually died. Is this because of their age? I give them slow-release fertilizer twice a year and water them weekly, if we're not having routine rains. I've had moths from the sod web worms in them, but that has happened in previous years as well. They were allowed to grow a little taller than I really wanted them to be, but yearly I do trim them down maybe only 3-4 inches. The first two photos are examples of the decline; the last photo are of the 'newer' boxwoods, in that they may be only 20 years old (vs. 25+). They seem to be doing better. Any ideas? Thanks!