Water lilies may flower at different times of day and for different lengths of time according to their variety. Tropical water lilies, in particular, may bloom at night and continue blooming until the weather turns cold.
Different types of water lilies call for a variety of environments before they can produce flowers. Hardy water lilies thrive in cold weather and can survive in shade, but they need as much sun exposure as possible for optimal blooming, according to the University of Illinois. Tropical lilies need several hours of sun exposure each day and cannot survive in freezing conditions.
Water lily flowers start to bloom about halfway into the month of May. Hardy water lilies bloom for a set period throughout the summer and fall, while tropical water lilies continue to bloom until the first freeze of the year, according to Utah State University.
Time of Day
Some water lilies bloom during the daytime hours, while others bloom at night. The University of Illinois states that hardy water lilies bloom only during the daytime. Tropical water lilies, on the other hand, may bloom during either daylight or nighttime hours depending on the variety, according to Utah State University.