Bougainvillea shrub showing very sparse new growth

wow, not a very active forum either. My guess (and it's a WAG) is that the cold killed it. Bougainvillea aren't very hardy in extreme conditions, afaik

We live in Texas, I bought a nice bougainvillea last spring but in November we had snow and December we had several freezing periods which dipped into the teen. I covered all my plants and placed them in our shed, the only one that survived was a Jasmine. Both my bougainvillea and Mandivulle froze. Didn’t know you could add lights and cover to help them stay warm. It was beautiful before the freeze, no signs it is coming back to life. Our hibiscus in the ground had tiny little growth. Will see. Still having some chilly morning. Had some unusual cold snaps here in Texas.