Depends on how permissions end up working out ex: who created it. Either way you should be able to do it from client, but I've seen it where permission issues stop you from being able to delete because they get created with wrong permissions or something.
I setup a new mail server with Maildir and imap and I can create and delete folders fine from the client though. But my old server which uses mbox occasionally does not let me delete folders if I create them.
Either way you should be able to just go on the server as root and do it manually.