The growth patterns of the two plants are quite similar, but with several key differences. Brazilian elodea has smooth and soft leaves which are always in whorls of three. Hydrilla leaves are harsh, brittle and scratchy to the touch and are arranged in whorls, up to five per node. Also, the blooms of Brazilian elodea emerge with two to four flowers from a single spathe, compared with the single flower of hydrilla.
