They should be green now! Feed from March/April.

Mine (as are quite a lot of my evergreen plants) are looking very sorry for themselves and "ungreen" - I'm fairly certain it will have been the very low temperatures, and today I checked and there are new little leaves beginning to develop already, so it isn't dead. I think you and I may have to be ready to cut off cold-damaged foliage when the new stuff gets going properly, and, as Bamboo says, start feeding in spring to help them recover fully.

I find they usually green up as the weather improves and a feed will also help.Dont know if yours are in pots but if so they can look sickly if not potted on every few years.You can feed with bonemeal or blood fish and bone or a soluble feed for quicker results.