Close up of bi-color four o'clock: This is a bi-colored four o'clock. I planted it from seed and it was a very prolific bloomer. This variety didn't grow as tall as my hot pink four o'clocks. It produced large tubers and can be a perennial in hardier zones such as mine.

Four O'Clocks are grown as an annual in colder climates, but here in zone 8, they are definitely a perennial. I planted that flower from seed and they subsequently grew enormous tubers which can grow deep into the ground, making them extremely difficult to dig up. They produce copious amounts of seeds, many of which will drop off before you get a chance to harvest them. For that reason, this can be very invasive. The height probably varies depending on the variety. My pink ones last year easily grew to 4 or 5 feet tall, however these bi-colored ones never got taller than about 2 feet.

Because of the invasive nature of their growth, they can easily choke out other plants that are growing around it. I would recommend pulling up the seedlings before they get a chance to grow any tubers. If you intend to plant four o'clocks, plant only a few seeds. You will get plenty of flowers from no more than a few seeds.