Mirabilis jalapa are commonly known as four o'clock, due to the fact that blooms unfurl about this time every afternoon and stay open into the night. It is also known as, Marvel of Peru, since it is a native of that country.
Mirabilis jalapa belong to the Nyctaginea family. Nyctaginea is from the Greek, nyx or nyxtos, which means, night-blooming. 
'Broken Colors' Photo by Dave's Garden member, Gabrielle
Marvel of Peru typically grows between three and four feet tall. It is not unusual for Mirabilis jalapa to grow three feet in diameter.
The plant makes a nice small bush with elongated, heart-shaped leaves from deep green to lime. The oboe shaped blooms in colors ranging from white, yellow, pinks, red and variegated begin their show in midsummer and continue well into fall.
Growing in Home Gardens
Reported by gardeners in subtropical and tropical climates to be a perennial plant, the Mirabilis jalapa can be grown as an annual in more northern climates. This should not deter the northern gardener from trying the plant though, as it will quickly grow and reward the gardener with blooms from summer through fall.
Marvel of Peru is a herbaceous plant that forms a tuber which allows it to return stronger in subsequent years.
Seeds form readily on plant and can be collected daily. Seeds can be planted outside after last frost. New plants grow quickly from seed.
4-O'clock Seeds, Photo by Dave's Garden member, Floridian
*Seeds are poisonous if ingested. Other parts of plant may also be poisonous. 
In northern zones, tubers should be dug and stored for winter just like any other bulbs and tubers in northern gardens.
Soil, Light and Water Needs
Marvel of Peru likes loamy but well drained garden soil. However, it will grow in poor sandy soils and is a good plant for xeriscaping. The difference may be in the color of foliage which will be darker green in richer soil but still a lovely plant in poorer soil.
In northern zones, the plant should be grown in full sun. The further south it is planted, a bit of dappled shade is preferable but not necessary.
In early spring, while plants are emerging, regular watering will get them off to a good start. Average water is all the plant will need the rest of the season. It will even tolerate drought conditions once it is established.
The sweet, citrus-like scent of the blooms entice the Hawk Moth, (Agrius cingulata), to pollinate the plants at night.
Hawk Moth, Photo by Dave's Garden member, frostweed
Mirabilis jalapa can be invasive due to the amount of seeds produced in one season. Many people consider it a weed but if there is plenty of empty room to be filled in the garden or along a fence line, this is a wonderful plant to fill the space.
Above photos by Dave's Garden members, tubbss5(top-pink/white), Thaumaturg(center-pink) hicochi3 (yellow/pink), Anitabry2 (top-pink/yellow), frostweed(White & Red)
Yellow 4-O'clock photo by Dave's Garden member, htop