Swordplants, Echinodorus species, grow in the wild as both submerse (during the rainy season) and emerse (the rest of the time). To grow these emerse at home you need to treat them as emerse bog plants with very high humidity (either in fully enclosed terraria or in a greenhouse under mist). Different forms of leaves are used in each situation - the submerse leaves wilt and die when emerse, being replaced with heavier leaves for air growth, and the reverse when emerse plants are moved to submerse growth.