Yucca gloriosa is normally planted outdoors, in a sheltered, sunny spot that doesn't get too wet. When you say 'palm elephantipes', do you mean Yucca elephantipes? If you do, that's not hardy, although the way to deal with it is to keep it outside during the summer months, so a pot that's big enough with good drainage which can be moved relatively easily is the way to go. It prefers a deep pot. This answer assumes you're in the UK...