Buxus
B. sempervirens_boxwood_box_krušpánek_zimostráz_???   Whatever name you like,  it is all about the same hardy plant.   Hardy?  For sure the bush is quite resistant to the attacks of many pests but as we know a keen non well seasoned greenfinger or a delicate moth could do a lot of damage to it.   Just have a look how this tree has looked like in spring 2018:             And now in winter  ( 30.12.2019 )         It looks a bit less regimented perhaps.  But if you look closer you will see a lot of dead branchlets all around the crown. See the pic below...      At the first thought about the reason I was quick to blame the vigorous blossoming in the previous year.  And based on that I have tried to strip as many new buds as possible.         Quite a job.  You need a good amount of time to deal with that.  The good point of it - it gave me a lot of time to think. And maybe having a bit deeper and more honest look on the possible root causes....