These plants do not open their flowers until late afternoon, and they stay open until the following morning. The blooms produce a fragrance that attracts night-flying moths, but some seem more fragrant to humans than others.

Linnaeus named the genus mirabilis which means admirable. Four–o'clocks are also sometimes called the "marvel of Peru," and they seem to grow so effortlessly that some gardeners think of them as weeds.

They bloom in the summer, like full sun and well-drained soil and have brightly colored, trumpet- shaped flowers that can be pink, white, lavender and yellow. They grow 48 inches tall with a spread of 12 - 24 inches so can make a good low hedge. They also are impervious to air pollution and have tubers that can be dug and stored over the winter in cold climates.

These plants have been grown for centuries and there are records from as early as 1540 of them being cultivated in European gardens. In Japan, the seeds were traditionally crushed and ground into a powder which women used as a cosmetic. In China, the blossoms were soaked in water to produce a dye. Our native Colorado four-o'clock grows robustly in sandy soil at high elevations.