Corkscrew Vallisneria is a member of the tapegrass plant family. It can grow up to 20 inches tall and it provides valuable refuge for timid fish and fry, which will actually encourage those shy species to venture into the open more often. Corkscrew Vallisneria should be planted with its crown above the substrate. It will establish strong roots and is unlikely to be uprooted by bottom-dwelling fish. Its leaves should not be trimmed, as they will typically rot and fall off when damaged.