The genus Nymphaea contains around 70 species spread across nearly every corner of the world, from hardy rhizomatous types that survive frozen winters in zones 3 through 9, to tender tropical varieties that demand warmth year-round and reward it with larger, more fragrant flowers in a wider range of colors. Hardy water lilies bloom at the water surface in reds, whites, pinks, and yellows; their leaves are thick, smooth-edged, and lightly mottled. Tropical types push the flower above the water on tall stems, and split further into day-blooming and night-blooming groups — the latter opening at dusk and closing the following morning.

All water lilies prefer still or slow-moving water and loamy soil with a neutral pH. They are heavy feeders and benefit from fertilizer formulated specifically for aquatics. Water depth should be matched to plant size — small varieties will thrive in a container as shallow as three inches, while larger ones need a foot or two of water and significant horizontal space. Propagation is by dividing rhizomes in spring, or by separating the plantlets that viviparous varieties produce attached to the mother leaf.