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Four O'Clocks (Mirabilis jalapa) Really Do Bloom in the Evening.

By , About.com Guide

Mirabilis jalapa (Four O'Clocks)

Pink Mirabilis jalapa (Four O'Clocks) and Blue Salvia.

Photo: © Marie Iannotti (2008) licensed to About.com, Inc.

Overview:

The cheerful Mirabilis jalapa got the common name “Four O’Clocks” because the flowers open in late afternoon. They remain open until morning and on cloudy days, they may not close at all. Their other common name “Marvel of Peru” is probably because they are native to the topical areas of South America. Mirabilis means wonderful, in Latin. Seeds are poisonous if ingested.

Some reports claim that the leaves are both attractive and lethal to Japanese beetles. I’ve never noticed this, but it might be worth an experiment.

Description:

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.

Latin Name:

Mirabilis jalapa, Synonym: Mirabilis lindheimeri

Common Name:

Four O'Clock, Marvel of Peru

Hardiness Zone:

USDA Hardiness Zones 7B - 11. Grown as a self-seeding annual elsewhere.

Exposure

Full sun. Four O’Clocks can take some shade, but at least 6 hours of sun is needed for best flowering.

Mature Size:

1 - 4' (h) x 1 - 3' (w)

Bloom Period

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..

Design Suggestions:

Since Four O’Clocks bloom in the evening, plant them where you’re sure to see them and catch a whiff of their fragrance. Pots on decks, along walkways and on the edges of seating areas. They mingle and grow through other plants nicely, making a nice underplanting. Hummingbirds are attracted to the tubular flowers.

Growing Tips:

Soil: Four O’Clocks ares not particular about soil pH, but does 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 in dry conditions.

Planting Four O’Clocks: Where perennial, you can divide and replant Mirabilis 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 over night, before planting, can speed germination, but the seeds germinate almost as quickly as they grow. Chances are god 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

Maintenance:

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

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 & Problems:

Rusts, (white rust and brown rust) and some leaf spot diseases can affect the foliage.

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