Which Flowers Close at Night?
Most of us know of a few flowers that close at night. This plant behavior is called nyctinasty, and it is the term used when flowers are open during the day, and then close at night. According to the online publication site of NewScientist, some plants open and close their flowers so punctually that it was once popular to plant them to resemble a clock face. Many species of flowers exhibit this behavior.
California poppies are versatile plants that can grow in a range of conditions. They grow well in open, grassy areas and in rocky, sandy areas. They are common in the western United States, in the Mohave dessert and into Northwest Baja. Poppies are usually orange, but sometimes bloom in yellow, and rarely in white or cream. Indians used these flowers for medicinal purposes, to treat headaches and insomnia. The flowers of poppies are responsive to sunlight, and close their flowers each night and on cloudy days. According to Rosemary Whittington in the BBC’s Focus online publication, poppies open and close to protect their pollen.
Kalanchoe plants are perennial evergreens. They sprout large, upright clusters of small flowers that range in color including shades of orange, red, and pink. Kalanchoe flowers open by the growth of new cells on the inner petal surfaces that force them out; the flowers close by the growth of new cells on the outer petal surfaces that force them inward.
African daisies are blooming perennials, or annuals, depending on where they are planted. They grow in small, dense mounds that reach about 20 inches in height. The leaves grow pale and slightly fuzzy, and they bloom brightly. According to the Washington State University Extension, African daisies are a variety of Osteospermum that close their blooms at night.
Morning glories are common ornamental vine flowers that are often considered invasive weeds because of their fast growth rate. These annuals attract both hummingbirds and butterflies. Morning glories close at night and reopen the next morning, hence their name.