Yes, it has to go below freezing for the blooms to open. We have only bee below freezing one time so far and that we the night it snowed. By 1 pm the next day it was gone, lol. I am sitting here with the doors open right now because it is so warm outside. The White flowered variety are the most common ones for tea making, but any of them will work. You can add in a little of this or that herb or spice to make it something uniquely you.