Winter Burn on Green Gem Boxwoods - March 2024

I planted a trio of Green Gem Boxwoods in the backyard in Fall of 2021.  That feels like an eternity ago, doesn't it?  They've had two full growing seasons (2022, 2023) and are headed into their third (2024).  They went in as tiny, one-gallon pots that were 50% off (my favorite price).   Looking back at their initial size, they've put on some good growth over the years, but they're certainly NOT mature just yet. 

This post talks about them being more dwarf in size - topping out at two-to-three-foot balls.  

Here's what they looked like last Fall - October 2023 - when I remarked that they had filled out.  

I was out in the yard this week and noticed that one of these Green Gem evergreen shrubs took on some Winter damage.  Dry, brown tips that appear to have died-back with the cold temperatures.  See below for a look at the winter burn/winter damage:

Over the Winter, I decided to pull a couple of boulders closer to the front of the border and sat a large square one right in the middle of these boxwoods.  You'l note that the damage isn't *just* on the side of the shrub that faces the stone, so I'm not of the belief that the boulder had anything to do with the damage.  

But, what else could account for this boxwood burn? 

I documented these same Boxwoods coming out of Winter a year ago (February 2023) with no winter injury.