Pruning Pinks

Hello all,

I have some rather nice pinks growing in pots on my balcony. I have a range of sorts which I started from plugs this year and have done fairly well. I know that they're pretty hardy provided they don't get too wet, but I have read somewhere or other that they benefit from a hard cutting back after the first frost. Does anyone practise this, or any other trimming or pruning? They seem to naturally form fairly tidy clumps.

Thanks,

Owen.