I grew valerian from seed this past winter and planted in the garden in mid May. I'm in zone 7b. My plants are huge and healthy, but they still have not bloomed and we are at the end of August. Do they take a year to bloom?

Evidently yours do. Yours are some very young plants. It's way past the time of year that Valerian blooms now anyway. Valerian is one of the very heaviest self-seeders in my garden, and if I didn't remove the flowering stalks before they set seed, I'd be spending my days digging up Valerian seedlings everywhere within thirty yards of it.