Four o'clocks, sometimes called marvel of Peru, open their blossoms each day in late afternoon and close them in early morning. They come in red, pink, yellow, white or striped varieties. They sometimes produce flowers of different colors on the same plant. In areas with mild winters, they can become invasive if the flowers are left to go to seed.
Chose the planting site. Four o'clocks do best planted in full sun in cooler climates, and with some afternoon shade in hotter areas.
Prepare the soil. Spread and inch of compost on top of the soil at the planting site. Turn over the top 6 to 8 inches of soil with a shovel, incorporating the compost into it. Rake the area smooth with a garden rake.
Scarify the seed. Rub each seed along an emery board or fine-grade sandpaper. This opens up the hard shell so moisture can penetrate the seed, hastening germination.
Plant the seeds ½ to 1 inch deep and 4 to 6 inches apart in rows that are 12 to 18 inches apart. They will germinate in about 7 to 14 days.
Thin seedlings when they are about 3 inches high so they stand 12 to 14 inches apart.