Personally i dont think you need to know programming to be good at security. There are lots of tools out there that have been written by others to help you with your security work. As long as you know your area of expertise well enough, not knowing programming wont cause too much problems,

After saying that, i have to add that understanding programming really helps a lot as you can understand how things work better and maybe able to solve problems yourself without having to rely on others to come up with programs to help you in your work.