This is a plant whose flowers you wait to see until afternoon -- hence, the common name "four o'clock." The name mirabilis is from the Latin "wonderful." They open in mid- to late-afternoon and close again the next morning (except on dull days).
Description of four o'clock: Four o'clocks form a well-branched, bushy shrub from 1 to 3 feet tall. Flowering is generous, with plants covered with white, yellow, red, purple, and unusual bicolored flowers. Sometimes different flower patterns appear on the same plant. When closed, the flowers curl up tightly.
Growing four o'clock: Full sun in average-to-rich garden soil is ideal for four o'clocks. They will also bloom in partial shade, although plants will become lankier. They are very tolerant of humidity, air pollution, heat, and drought, Plant them outdoors once the danger of frost has passed. Since they are vigorous growers, space them 18 to 24 inches apart. Four o'clocks form tubers which, after frost, can be dug up and stored for replanting the following year. Four o'clocks reseed.
Propagating four o'clock: By seed or by tubers. In warm climates with a long growing season, you can seed outdoors after the last frost. For shorter season gardens, you'll get earlier bloom by starting them indoors 4 to 6 weeks ahead of planting out. Seeds germinate in 7 to 10 days at 70 degrees Fahrenheit.
Uses for four o'clock: Four o'clocks make a neat, low hedge. They can be used for edging walks and borders or grouped in the center of the border. Because the flowers stay open at night, they're attractive when planted near evening activities -- such as lighted pools and patios. Four o'clocks also grow well in large containers.
Four o'clock related varieties: Jingles bears white, rose, red, yellow, and crimson flowers, many of them splashed with contrasting colors. Tea Time series and Afternoon Delight offer a range of colors.
Scientific name of four o'clock: Mirabilis jalapa