How to Grow Four O'Clocks (Mirabilis Jalapa)

Four O'Clock Flowers (Mirabilis jalapa)

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Fragrant, cheerful Mirabilis jalapa goes by many names. The most popular name, “Four O’Clocks” came about because the flowers open in late afternoon. Four O’Clock flowers remain open until morning and on cloudy days they may not close at all. Another common name “Marvel of Peru” is probably because they are native to the tropical areas of South America. And Mirabilis means wonderful, in Latin.

Four O’Clocks are a bushy, tender perennial that can be grown from either a tuber or seeds. In ideal conditions, they can become a nuisance, but gardeners in cold climates can keep the re-seeding under control.

  • Leaves: Opposite, slightly pointed oval leaves and multi-branching stems.
  • Flowers: Trumpet-shaped, 5 petal flowers come in pink, red, yellow, white and some bi-colors. Flowers have a slight vanilla scent and open in the late afternoon through the evening.

CAUTION: The seeds of Four O'clocks are poisonous if ingested.

Botanical Name

Mirabilis jalapa, Synonym: Mirabilis lindheimeri

Common Names

Four O'Clock, Marvel of Peru

Hardiness Zones

Four O'Clocks are reliably hardy in USDA Hardiness Zones 7b - 11. If you live in a cooler zone, don't let that stop you from growing them. They can easily be grown as an annual flower and will graciously self-sow in your garden.

Sun Exposure

You will get the most flowering if you plant your Four O'Clocks in full sun. The plants can take some shade, but at least 6 hours of sun is needed for the best flowering.

Mature Plant Size

Expect your plants to grow 1 to 4 ft. tall x 1 to 3 ft. wide

Bloom Period

Once Four O'Clocks get going, they will bloom from mid-summer to fall.

Suggested Varieties

  • Mirabilis jalapa Mix - Old-fashioned self-seeding Four O’Clocks in mixed solid colors.
  • Mirabilis jalapa "Alba" - Self-seeding all white Four O’Clocks
  • "Jingles" cultivars - Smaller plants with two-tone and multi-colored flowers.
  • Kaleidoscope - A hybrid with multi-colored pink, yellow and white blooms.
All white four o'clock flower
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Design Suggestions Using Four O'Clock Flowers

Since Four O’Clocks bloom in the evening, plant them where you’re sure to see them and catch a whiff of their fragrance. Place pots of Four O'Clocks on decks or plant along walkways and on the edges of seating areas. They mingle and grow through other plants nicely, making a nice underplanting. Hummingbirds will visit your garden because they are attracted to Four O'Clock's tubular flowers.

Four O'Clock Growing Tips

Soil: Four O’Clocks are not particular about soil pH, but do best in a soil that is neutral to slightly acidic. They are heavy feeders, though, and a rich, well-draining soil is ideal. They can go dormant if left in dry conditions for too long.

Planting Four O’Clocks: Where Four O'Clocks are perennial, you can divide and replant the tubers pretty much anytime. In colder climates, tubers can be dug and stored in the fall, to be replanted when the soil warms in the spring.

Four O'Clocks can also be grown from seed. The easiest method is to direct seed them outdoors, just before your last frost date. Soaking the seeds overnight, before planting, can speed germination, but the seeds germinate almost as quickly as the plants grow. Chances are good that if you allow your plants to go to seed in the fall, they will self-seed in the garden. Seedlings can be easily pulled and moved to another section

Caring for Four O'Clock Plants

Where perennial, cut back old Four O’Clock stems in the spring and give them a shot of fertilizer, if your soil is poor. Mulch around the plants, to keep the soil moist and the plants blooming.

Because Four O’Clocks bloom so profusely, keeping them deadheaded is all but impossible and they don’t really need it to keep blooming. In drier seasons, when the plants can get a little ragged looking, a shearing back by about 1/3 will refresh them. In very dry conditions, the plants can stop blooming entirely, until they are revived with some water.

Pests and Problems of Four O'Clocks

Four O'Clock's tend to be very pest and disease resistant. however, rusts, (white rust and brown rust) and some leaf spot diseases can affect the foliage.

On a positive note, some reports claim that the leaves are both attractive and lethal to Japanese beetles. This may or may not be true, but it might be worth an experiment.