Not advisable. While you can insulate it. During a power outage when its below freezing outside, it will freeze. Adding glycol to the system is an option, but reduces the amount of heat output to the baseboards.
Another option is to run the baseboard cover from one end of the room to the next, and wrap it at an inside corner. And bring the pipe up in that inside piece.
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.