Phlox subulata pruning

Should I trim the brown bits off my Phlox subulata or will it all go green? Can I do anything to stop it going brown in the winter? I have several species and they have all behaved slightly differently. Last year I rescued some from a friend who had left them in tiny pots for a couple of years. I repotted them and pruned them hard and they did grow back so I planted them out. Some were mine and they had been in reasonable sized pots for a year and they all did well very early. They were in pots as the planting area took much longer to excavate than anticipated.
Thanks for your advice