Available in white, yellow, pink, red and mixed, the flowers of Mirabilis jalapa (commonly known as four o'clocks or Marvel of Peru) open in late afternoon/early evening and close the following day before noon, living up to the plant's latin translation: marvelous or astonishing. A perennial from tropical America, the Mirabilis jalapa is cultivated in the United States as an annual except in USDA Zones 8-11 where it thrives as a perennial. Heat- and drought-tolerant, four o'clocks are easily grown from seed and will often return from tubers year after year where winters are relatively mild. Growing two to four feet in height, the plants prefer full sun and tolerate a variety of well-drained soils.
Mirabilis jalapa is particularly suited for the quaint cottage gardens for which the rural American South is known, but the plant also deserves a rightful place in formal locales where it is capable of adding interest and contributing a vibrant kaleidoscope of color at a time of day when many other flowers are fading or well spent. Four o'clocks can even be found growing at historic Monticello Plantation, Thomas Jefferson's estate in Albemarle County, Virginia. Upon observing the flowers in his garden, Jefferson noted in July 1767, "Mirabilis just opened, very clever." Monticello's records further indicate that seed were received from André Thouin of the famous Jardin des Plantes in Paris in 1811.
It's no wonder the plant that awed Jefferson over two centuries ago continues to impress gardeners today. Wonderfully fragrant, the blooms perfume the air, making four o'clocks ideal for planting near patios, decks, screened porches and backyard swings where they can be enjoyed to the fullest extent while conversing with family or friends, sipping iced tea or lemonade and hopefully relishing an evening breeze.
The downside to the prolific bloomer is its abundant crop of seed. Judicial culling of unwanted seedlings each spring and digging of tubers each fall might prove necessary, but inevitably some seedlings will be overlooked and portions of tubers often remain undug and subsequently new plants emerge. Mirabilis jalapa is best planted in containers of generous size or situated in a bed where it can freely colonize.
Joseph Breck, The Young Florist (Boston: Russell, Odiorne & Company, 1833).
Bill Scheick, "It's time again for four o'clocks," Dallas Morning News, July 13, 2007.