Raoulia australis (NZ silvermat) winter dieback repair?
 

We have some of this lovely groundcover (Raoulia australis) growing between slate flags in a rock garden. Normally it does very well depending onb the winter (Zone 9a). This winter some of it has died off between some of the flags.

I wonder how we should deal with the dead patches: just hope it grows back and through the old mat, remove the dead material, or just trim the dead material? Any ideas appreciated.