Bougainvillea Plant , Winter Care.

Last year I lost my beloved white bougainvillea after a winter storm that was too cold for my little greenhouse to handle. This year I am going to double up the plastic sheeting. I'm using a 6 mil plastic sheeting so I'll add a second layer which will make 12 mil. I hope and pray that this will keep my Bougainvilleas a lot warmer than last year. Luckily, last year I only lost the white Bougainvillea. This year I have much more to lose, as I have purchased more Bougainvilleas and my original Bougainvilleas are growing and looking magnificent, so I really want them protected in these little greenhouses.