curl is a very powerful utility. It even can upload a file to a FTP server (-T option) and it's possible to create a directory on the remote FTP folder by sending an arbitrary command:
curl ftp://server/existed_parent_folder/ -Q -"mkd new_subfolder_name"
Here "mkd" is the server's command.
To know the list of the server commnads, execute:
curl ftp://server/ -Q -"help" -v