Cutting back four o’clocks

Kick Off Happy Hour! How to Grow Four O’ Clock Plants from Seed

October 02, 2018

When our workday is done, four o’clock plants are just getting started. Many members of the Mirabilis family earned the common name because their blooms open as the ambient light fades, and wilt with the new day.

But…why plant four o’clock if the flowers are so short-lived? Because they’re continuously in bloom throughout the season, and each blossom produces copious amounts of nectar to attract butterflies, birds, bees, and moths that prefer cool evenings or late nights to feed on and pollinate your garden.

Our favorite species, and the one we recommend for your garden, is Mirabilis jalapa. It’s very easy to grow, works well in planters, large baskets, and most anywhere you want to create a tropical aesthetic, and its ability to thrive in wet, riparian areas makes it a great choice for small-scale sustainable erosion management.

Mirabilis Jalapa and the Four O’Clock Family

Four o’clock is the most recognized name for Mirabilis jalapa, though it’s also applied to many other species within the genus. Mirabilis means “wonderful,” and the genus name is for the Mexican city Xalapa. Common names specific to M. Jalapa include:

  • Beauty of the night (with or without hyphens)
  • Marvel of Peru (with or without hyphens)
  • Coat of many colors
  • Mirabilis lindheimeri (alternate but outdated botanical name)

Mirabilis jalapa is part of the Nyctaginaceae family. Also known as the “four o’clock family” Nyctaginaceae includes about 30 genera and 300 species, including bougainvillea and abronia

M. jalapa is native to tropical South and Central America, and since its discovery by Europeans in 1540 it became a popular garden plant in the Old World. It quickly naturalized in tropical climates, including Africa, Australia, and New Zealand.

Four o’Clock Gets Sloshed: Water Runoff Management

Mirabilis jalapa is a recommended specimen for rain gardens, sustainable landscapes designed to slow the surface path of water that is shed from buildings, sidewalks, driveways, and roads during heavy rainfall. Rain gardens reduce erosion, filter pollutants, and reduce the volume of water entering stormwater systems.

Learn more about rain garden design from the Groundwater Foundation.

Moon Gardening with Mirabilis Jalapa

Since four o’clocks open up in afternoon shade or during the waning sunlight, they’re lovely companions for evenings on the patio. On a single plant, some flowers might not have a fragrance, but most usually do, lending a sweet aroma to the summertime air.

Moon gardens are aesthetically pleasing to the night-owl gardener and nutritionally important to nocturnal pollinators, including hawkmoths and sphinx moths.

Growing Conditions for Four O’Clock

Tropical M. jalapa requires different growing conditions to those Mirabilis varieties native to the northern continental regions. Be sure to check your seed packet to verify the plant’s botanical name. In comparison to M. jalapa, other four o’clock species are teetotalers, withstanding drought and less-than-lush conditions.

Reputable garden experts, including Cornell’s online garden guide, often don’t differentiate between species and offer growing advice that’s unsuitable to the tropical four o’clock species; for example, they recommend M. Jalapa as a drought-resistant xeriscape plant. This is true of some Mirabilis species, but certainly not those we’re spotlighting in this post.

It’s like assuming someone wants gin in their martini instead of vodka.

In any case, all four o’clock species are easy to grow and require little maintenance other than that which might tidy up your flower beds. If you’d like more information on species native to the United States Southwest, check out the Utah State University Extension page on the Mirabilis genus.

USDA Hardiness Zones: Mirabilis jalapa is typically grown as an annual throughout North America, though it’s classified as a long-lived, tender perennial in zones 7-11.

Sunlight Preferences: Full sun to partial afternoon shade.

Moisture Requirements: M. jalapa demands average to consistently moist conditions, and can withstand wet soils if they have good drainage. Don’t let them dry out.

Soil Preferences: Plant your four o’clock seeds or transplants in nutrient-rich soils with a neutral to slightly acidic pH.

Plant Size: 2′ to 3′ tall and wide.

Growth Habit: Dense, rounded and shrublike.

Root Structure: In regions where they thrive as perennials, M. jalapa develops deep, tuberous taproots that, in older plants, can weigh in at more than 30lbs.

Bloom Period: The flowers begin their afternoon celebrations mid-summer, with the first fall frost ringing the bell for last call.

Flowers: Trumpet-shaped four o’clock flowers resemble smaller (2″ long) versions of the hibiscus. Coloration includes solid, spotted, or variegated shades of white, pink, yellow, red, or magenta. It’s not unusual for a single plant to produce different colored flowers. Each self-pollinating blossom produces a dark brown single-seed pod (anthocarp).

“The colorful, trumpet-shaped portion of the flower is the pigmented calyx or partially fused sepals; the flowers actually have no petals.”

— University of Wisconsin Extension Master Gardener Program

Blooming four o’clock flowers can have a very strong, sweetly-scented fragrance, or no odor at all. The blooms open when the plant becomes shaded, or when ambient daylight decreases, and wilt the following morning. Mirabilis flowers usually bloom in trios.

Foliage: The bright yellow-green to dark green leaves are wide, tapering to a sharp tip, growing up to 4″ long. They’re arranged on the stems in an opposite pattern.

Pests & Diseases: Four o’clock plants are disease and pest resistant, but look out for aphids on younger plants. The foliage is rumored to attract and then kill Japanese beetles, but there’s no scientific evidence to back up these claims. Water them at soil level when possible, or early in the day so their foliage can quickly dry, preventing leaf spot.

Maintenance: Spent flowers don’t naturally fall off, requiring them to be hand-picked when the plants become too shabby. Most gardeners simply cut their plants back by about a third to reinvigorate them, since the plants are in continual bloom and deadheading is a Sisyphean task…and cuts into cocktail hour activities.

Mulch around the base of your plants to help them retain moisture, and give them a shot of fertilizer each spring and once or twice through the growing season to keep these heavy feeders in full flower production.

Growing Four O’Clock from Seed

Dig a good shovelful of fine, rich compost about a foot deep below surface level to accommodate four o’clock’s long taproot, and be ready to keep the area consistently moist during and beyond germination.

Seed Treatment: Mirabilis seeds can remain dormant for years. When growing four o’clock from seed, we recommend either (or both) a good overnight soak in lukewarm water, or mechanical stratification by scoring or lightly sanding the seeds to assist in germination. For the latter, a few passes with an Emery board work well. For more tips on treating seeds prior to planting, check out our post, “The Dirt on Successful Seed Germination.”

When to Plant Outdoors: Direct sow seeds after all danger of frost has passed.

When and How to Plant Indoors: Sow your four o’clock seeds indoors 6-8 weeks prior to your last frost. Protect the growing taproot by planting in peat pots or CowPots™, and consider growing and watering them in capillary trays to encourage root growth from the bottom. If you don’t have overhead fluorescent lights and sub-tray heat mats, germinate your seeds in a warm, sunny window.

Seed Depth: Plant 1/4″ deep. M. jalapa seeds are larger than most that require sunlight, so they shouldn’t be surface sown.

Seed Spacing: Plant or thin 12″ to 18″ apart.

Days to Germination: 7-14 days at 70°F.

Transplanting Tips: Soak and score your peat pots and plant them in loose, damp-to-wet garden soil. Take care not to damage the growing taproot.

Uses for Four O’Clock

Crushed four o’clock flowers are a traditional source of dye for textiles and food coloring. While the flowers are considered edible, we suggest you opt for a traditional salad bar if you need a snack.

There is plenty of anecdotal evidence that native North Americans used some Mirabilis species for medicinal purposes, and that Aztecs and South and Central American cultures used M. jalapa tubers and leaves for addressing the following health issues:

  • Impotence (must be the whole “big taproot” thing)
  • Constipation
  • Leprosy and other skin lesions
  • Menstrual disorders
  • Scabies
  • Muscular swelling

Note, different parts of the plant are used for different applications, often combined with other plants for the desired effect. We strongly advise that you find alternative remedies for whatever ails you. Maybe start with a cocktail…but don’t hold us liable if you experiment with any Mirabilis plants for any medical purposes, or if you have one too many adult beverages and do something irresponsible, embarrassing, or worthy of a YouTube fail video.

Four o’clock seeds are poisonous if eaten. If your pets or kids are in the habit of eating hard, miniature (3/16″) bunny turds in your garden, they might accidentally ingest four o’clock seeds. Discourage them from eating other parts of the plant, as well.

Our Seeds are Top Shelf

At the end of the day, you want to enjoy all your hard work in the garden. Reward yourself by enjoying a nice, cool beverage as you watch fresh four o’clock flowers wake up to help you greet the evening.

Your best bet for a productive season is an investment in high-quality, fresh seeds. At Seed Needs, we only keep enough seeds in stock that we can expect to sell in a season, and we purchase our products from sustainable producers of disease-resistant and vibrant genetics. Contact us if you want to learn more about our commitment to helping you achieve gardening success, or to order the best quality seeds available.

Why settle for bathtub hooch when you can order top shelf quality?

Magenta four o’clocks blooming in a garden.

The common name of four o’clocks was given to Mirabilis jalapa because the flowers of this plant do not open until late in the day. This old-fashioned garden ornamental in the four-o’clock family (Nyctaginaceae) is a tender perennial hardy in Zones 7-10, generally grown as an annual throughout most of the US. Native to tropical South America in the Andes – and also sometimes called Marvel of Peru – it is the most commonly grown ornamental species of Mirabilis. Discovered by Europeans in 1540, the root was used by indigenous peoples for medicinal purposes, as a hallucinogen, and as a purported aphrodisiac, while the flowers produce an edible red dye for coloring food.

The shrub-like plants have medium green foliage.

The shrub-like, erect and spreading, multi-branched plants grow 2-3 feet tall and wide. The weak and brittle stems break easily and flop over if not supported. They are light or bright green, but may have a yellow or pink hue. The opposite, ovate, bright green leaves are up to 4 inches long with a pointed end.

The swollen root of MIrabils jalapa.

They are triangular to egg-shaped to lance-shaped, with smooth (non-toothed) edges. The plants produce elongated, dark-colored, swollen to tuberous taproots that can be a foot or more long and weigh up to 40 pounds in climates where they are perennial.

Flowers are produced in bright and pastel shades of white, yellow, pink, magenta, and red. Flowers of different colors can be found on the same plant – either simultaneously or at different times – and flowers may even be bicolored, speckled, or variegated.

Four o’clocks come in a variety of shades and colors.

They bloom in summer through fall and may have a strong, sweet-smelling fragrance when open (but sometimes have no noticeable scent). Flowers are borne in terminal or axillary clusters of one to several flowers. The colorful, trumpet-shaped portion of the flower is the pigmented calyx or partially fused sepals; the flowers actually have no petals. Each flower is about two inches long and abruptly flares out to about an inch across at the end with five lobes. These tubular flowers open late in the day or in the evening (although they will open earlier open earlier on rainy or very cloudy afternoons) as they are pollinated by sphinx moths (family Sphingidae) and other nocturnal pollinators with long tongues. Hummingbirds and butterflies are also attracted to the flowers.

The flower buds (L), open flower (LC), fading flower in the morning (RC), and plant with many spent flowers (R).

The flowers wilt by the following morning and those faded flowers are not self-shedding, remaining on the plant – so some people may not like the appearance. Numerous large, dark, leathery, 5-ribbed, spherical “seeds” (actually a fruit that is a nut-like achene) with a wrinkled surface are produced in the fall. These are poisonous if ingested. They can also self-seed under the right conditions and have become naturalized in some parts of the southern US.

The wrinkled, dark-colored fruits on the plant (L and C) and harvested (R).

Grow four o’clocks in full sun.

Grow four o’clocks in full sun in almost any type of soil, but they do best in a humus-rich, well-drained spot. Plants can be started from seed sown outdoors after the danger of frost has passed or indoors up to 8 weeks ahead of time. Soaking the seeds in water overnight will speed up germination. Sow the seeds no more than ¼ inch deep as light aids germination. They should germinate in 1-3 weeks. Transplant seedlings when large enough to handle, if needed, into individual. Thin seedling or place transplants 12-24 inches apart.

Seedlings of Mirabilis jalapa (L) and with first true leaves (R).

As these are tender plants, put transplants outside after all risk of frost, about the same time you would plant tomatoes. Provide moderate moisture and fertilize periodically for the best growth. They have few pests and are not favored by deer. Tubers can be dug in the fall to store indoors and plant again in spring after the last frost. Treat the tubers like dahlias, digging them before the first freeze, shaking off the soil and storing them in dry, cool but frost-free conditions.

Four o’clocks are a good addition to an annual garden.

This sturdy plant can be used as an annual hedge if planted close together. They are right at home in a cottage garden, in borders and beds, or can be added to large containers. If possible place them along on lighted walkways where the night-blooming flowers and fragrance can be appreciated. They combine nicely with Asiatic lilies, creating an interesting contrast of large and small flowers.

There are some cultivars and hybrids of four o’clocks, although they are often offered just as ”Four O’Clocks”.

  • ‘Broken Colors’ – has flowers splashed or marbled in orangey-red
  • ‘Jingles’ is a series with small, multi-colored flowers.
  • The related M. longiflora has white flowers with an orange-blossom scent.

– Susan Mahr, University of Wisconsin – Madison


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Four O’clocks –Right On Time

You can’t exactly set your watch by the colorful four o’clocks in your summer garden, but their timing is pretty good.
The bloom time of four o’clocks (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 p.m., or a bit earlier on cloudy afternoons.
Their abundant, trumpet-shaped blooms may be bright yellow, white, magenta, or wonderfully striped or splashed with pink, orange, or yellow. Sometimes several flower colors can be seen on the same plant. The flowers are fragrant, with a scent that is both lemony and sweet, and hummingbirds and moths are attracted to them.
Four o’clocks are easy to grow from seed. Plants get to be two or three feet tall in sunny spots or in part shade, and they bloom from midsummer until frost. In relatively warm-winter climates, four o’clocks will come back every year from tubers that overwinter in the ground. Seedlings can be a nuisance, but sometimes they find their way to the most interesting places in the garden, and plants you don’t want are easy to weed out when they’re small.
Four o’clocks are old-fashioned favorites for a commuter’s garden, says Peter Loewer, author of The Evening Garden and an expert on the flowers that bloom from dusk until dawn. Moonflowers, evening primrose, flowering tobacco (Nicotiana alata), some tropical water lilies, and even a few daylillies also bloom in the evening, which makes them nice choices for around a patio, where you can enjoy their flowers after you get home from work. They’re especially pretty on moonlit nights, and in the flash of fireflies.
Flowers around the clock
Morning glories and most daylillies are among the first flowers to open on a summer day, and poppies, zinnias, and marigolds follow along early in the day. By noon, the morning glories have usually closed up shop. When evening comes, it’s time for the four o’clock, moonflowers, creamy-white tuberoses, and other night bloomers — many of them fragrant. Phlox, flowering tobacco, and lillies are all especially fragrant in the evening, but if you’re up early, you may also catch a whiff of them, and of your four o’clocks, on your way to work in the morning.

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