Depends on the heat pump. If it’s not designed to run low temps I would think you would have noticed by now unless it’s warmer there than here in mi. It might freeze up, just make sure to have a safety high temp shut off on your lights and if possible a monitor for temps.
If possible you can block the wind and weather from it you might be able to get a few extra degrees out if it , common sense applies here but some people don’t have it so I’ll say you can’t completely block the condenser off. For instance I have lattice around mine and a roof over top of them, but they still have several feet around them so the air flow isn’t restricted.