Flowers open and close in reaction to temperature and light. Many, such as roses, snapdragons, daisies and geraniums, stay open once they bloom, whether it's daytime or nighttime. Others, such as four o'clocks, open in the late afternoon in reaction to cooler temperatures. And still others, such as angels trumpets, bloom at night.
Gazanias are daisy-like flowers about 2 inches in diameter in shades of white, yellow, pink and orange, often banded in contrasting colors. The plants are short--only about 12 inches high. They grow as perennials in mild winter areas. The flowers resist drought and will grow and bloom in poor soils. Gazanias grow best in sun; if they are planted in shade, its flowers won't open.
These flowers self-seed prolifically and will come back year after year. The feathery leaves and stems are a dull gray-green but the flowers make up for it by blooming in bright orange. The plant usually stays about 12 inches high but will reach 24 inches high under optimum growing conditions.
Another flower that spreads quickly and returns year after year if you let it go to seed is the African daisy. When removing plants, give them a good shake over the ground to release the seeds. The plants are short--only 12 inches high--and produce small, dark green leaves. From early to late spring, the plants are all but covered with daisy-like flowers in shades of yellow and orange. Plants are drought tolerant and will grow in poor soil.
Morning glories open only in the morning and close through the rest of the day and at night. The flowers are blue and trumpet-shaped with a wide flare. They grow up to 20 feet long and need a light support, such as fishing wire held by cup hooks. Morning glory seeds contain a substance called lysergic acid amide. Ingesting the seeds results in hallucinations similar to that of LSD, according to eBasedPrevention.org
Hardy Water Lilies
Water lilies come in two varieties: hardy and tropical. The tuber of the hardy water lily will live through a cold winter to re-bloom the next spring while tropical lilies won't. Water lilies have flat leaves, sometimes called pads, which float on the surface of the water attached to the roots of the plant by long stems. Hardy water lilies come in pinks, yellows and whites with yellow centers. The flowers close at night and reopen in the morning. Each flower lasts from two to three days.