I imagine the answer depends on your winter climate. If you're in a cold area I'd leave the tops as winter protection, along with any leaves that get caught in the stems. In my climate you could cut it back now.

I cut the height back by 1/3. Where are you located? Just the nearest large city,

I agree with floral_uk that winter climate makes a big difference here. In a colder spot I would leave more of the stems standing as protection and just clear the loose leaves around the base. Cutting it back by about a third, like peren.all suggested, seems like a safer middle ground than cutting it really short before winter.