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- Mirabilis lindheimeri (alternate but outdated botanical name)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 abroniaM. 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."
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)
- Leprosy and other skin lesions
- Menstrual disorders
- 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?