Four Oclock Flower Care. The bloom time of four oclocks Mirabilis jalapa is said to correspond to changes in light and temperature so they open in the cool of the evening usually between about four and eight pm or a bit earlier on cloudy afternoons. Sep 21 2017 Dig the four-oclock tubers from the ground by starting 12 inches from where the plants were growing and digging down as much as 18 inches.
A mature plant will have hundreds of magenta-pink flowers open at one time. In colder climates they are grown as annuals or at the end of the season the tubers are be dug up and stored indoors during the winter like dahlia tubers. On cloudy days the flowers open earlier and sometimes wont close at all.
Four OClock flowers only open in the afternoon around 400.
The plants are quite large growing 2 to 3 feet tall and wide. FOUR OCLOCK FAMILY Habit. The plants are quite large growing 2 to 3 feet tall and wide. Once established it grows.