How to Prune moss phlox?
No pruning required

moss phlox · Phlox subulata 'Nettleton Variation'
Also known as: mountain phlox; moss pink
Will perform best in well-drained fertile soil in a sunny or dappled shade positon, prefering full sun and avoiding waterlogging. Can be trimmed back in autumn to rejuvenate and shape.
No pruning required