Water-hemp or waterhemp is a common name for several plants and may refer:
In the genus Amaranthus: Amaranthus australis - southern water-hemp Amaranthus cannabinus - salt-marsh water-hemp, tidal marsh water-hemp or water-hemp pigweed Amaranthus floridanus - Florida water-hemp Amaranthus tuberculatus - rough-fruit water-hemp or tall water-hemp
In other genera: Ayapana triplinervis