there is a blight that attacks boxwood and it is almost always fatal. I do as you, cut the brown asap but eventually I end up with a scrawny shrub. What I've been doing is buying little 1 gal boxwood to plant so that when big shrub has to be removed, I have a little one growing. I think underwatering could also be a reason. as is dogs peeing on them. I know, as I've had all 3 things happen to me. I have a huge row and not really an option to remove all. I will continue to fill in the gaps with new boxwoods. Some people say that blight might remain iin the soil, thus contaminating new plantings, but I've yet to have that problem.

Hi. Thanks for the reply. These shrubs are in the front of my house and get no dog pee (my four legged boys reside in the backyard). Lack of water is not a problem either (as they sit right under the drip edge of the roof...and we get pleny of rain here). I guess I'll consider nurturing a backup in a seperate container. Can this blight "leap" from shrub to shrub? It's just odd that after all these years of healthy growth the browning starts. Cheers.

Yes, I believe it is contagious but IME, it seems to attack otherwise stressed plants. here is a link that may be useful

http://pubs.ext.vt.edu/PPWS/PPWS-29/PPWS-29-pdf.pdf

Thanks for the link. I appreciate it. Cheers.

I saw my pooch watering this boxwood

Here is an awful looking gap from trimming dead brown stuff. I haven't planted replacement yet. Takes about 1-2 years for gap to fill nicely.