Argarvie and frost

We are covering the banana plant to protect it from frost.There are 3 large argarvies in the garden which we usually cover but do we still need to do that now they are big?as it does look a bit of an eye sore through winter.I noticed along the seafront where we live the council doesnt cover them but they are right by the sea air.
The leaves are pointing more upwards so water wont lay and freeze so easily on them but obviously they will be open to the general jack frost!

It depends how big the Agave is and what lows you get,we have a big one which gets left unprotected for most of the winter and it does fine;what they don't like is cold wet otherwise they can tolerate pretty low temperatures.
  They can recover from winter damage quite quickly,a variegata we had lost it's centre spike completely one winter but it's still growing well now and has produced contless 'pups' as well.