I'll be curious what the experts on this forum say, but I think that may be boxwood blight. I have a row of about 10 boxwoods in my side yard that are exhibiting a similar phenomenon. I'd heard about boxwood blight and the images track with what I've found on the topic. It's apparently very difficult if not impossible to cure.

That was my first thought as well, based on the initial appearance. However, Sprinter ('Bulthouse') box is one of the limited number of cultivars that have shown high resistance to boxwood blight.

Doesn't mean it is immune.....just rather unlikely that may be the culprit.

Could it be frost? I had some plants that overwintered fine until a March thaw followed be a very cold, windy few days. If it's frost damage cut it off. If it might be blight, be sure to clean your secateurs between cuts. Rubbing alcohol should do the trick,

z5 is about half the US... give us a big city name.. to narrow it down ...

how long have they been planted??.. give us some history.. not just current status ..

what was winter like??

second from last pic.. are they against the house.. what direction does house face.. or is that a sidewalk ...

ken

The app won't let me respond to each comment so I'll add info here.  I'm zone 5 in Canada, near peterborough, Ontario. Yes it was a fairly harsh winter.  They are far from the house, along a stone pathway. They are planted in plenty of soil, and the mulch was on all winter.  They were planted this time last year.

So they are out in the open?!?!? Without shade, or windbreak or any other sort of protection? Ouch.

During the winter, boxwoods need shade and wind protection. Otherwise, they burn and look like those pictures. They just need careful siting in zone 5. For years, the only decent specimens I saw around here were in the front of a local library. They were flanking the steps of a building facing NNE, with a shelter belt of trees about 100 ft in front of them. The building shaded them from the sun, and the tree protected them from the winter winds.