Hi Patio, welcome to G O Y , no you don't need to cut them back, just tidy up any dead leaves, I find scissors the best tool for this job, if they're quite large and you want to divide them, you could probably get away with doing it now, as it's a late spring, but if they have a lot of new growth, leave until next spring, and split them towards the end of march before growth commences, Derek.

Yes I just pull off the dead leaves from lst year . then I have been know to cut off brown leaf tips to make the plant look better. if there are any dead flower spikes from last year then cut them out too.