And timing that final trimming before the cold temps of late fall and winter come is a science! I'm still trying to get it right. Nell, you're boxwood looks very healthy. I too cut holes into sides every now and then to let the sun penetrate.

Are we to assume you are in Towson, MD? Google "boxwood blight". Some varieties are resistant. They may nor may not have resistant varieties, but McLean Nursery on Satyr Hill Rd. usually has very reasonable prices on boxwood rooted cuttings if you want to go that route. It will require patience, of course. Don't let them talk you out of getting a resistant variety. Nurserymen can be overly optimistic about "the disease isn't going to get here". It will.

think in tree shrub time... which is years ... or even decades ... not one season or two ... all plants releader ... if you have the patience to wait for it ... this injury is not going to change the genetics which tend toward pyramidal yes.. you can guide it along ... but i would give it at least a year and a half to see how it sorts itself off ... thru next summer .. with no insult to the roots ... it should respond quick enough ... perhaps next fall .. you can select one leader.. and remove any extras ... to further the process .. now.. all that said ... if its right out the front door.. and simply going to drive you insane ... just get rid of it ... and move on with your life ... its not some rare specimen ... replace it.. if it will cut out any stress ... maybe move it out back.. where it wont bug you so much.. and plant something else here ... ken

They seem to have plenty of leaves on the outside so presumably it's just the normal aging and dying of the oldest leaves - broadleaf evergreens often shed these during the growing season rather than in fall or fall only. Sometimes for months at a time, as with Magnolia grandiflora. When it looks like there is a problem with old leaves dying off is when shrubs are starting to become see through (gaunt or sparse looking) because of it. A common cause of this is soil moisture problems, either too much or not enough. Otherwise too many leaves aging out and dropping at the normal time, when there is not a soil moisture problem discovered can be a soil mineral deficiency response. Lack of nitrogen for instance, with the shrub concentrating what minerals it still has present within it in the youngest leaves nearer the shoot tips.