Ornamental · Nyctaginaceae
Four O'clock
Mirabilis jalapa
The flower that times itself to your evenings, opening fragrant blooms at dusk all summer and returning on its own next year.
Full sun
Every 3–7 days
50–86°F · 10–30°C
60–80 days
Overview
Four o'clock keeps unusual hours, and that is the whole charm of it. The trumpet-shaped flowers stay closed through the bright glare of the day and open in the late afternoon, lending an evening terrace or a patio supper a sweet, drifting fragrance that draws moths and hummingbirds into the scene. A single bushy plant can hold blooms in several colors at once, sometimes striped or splashed on one flower, so a small planting reads richer than its size.
It settles into a garden quickly, reaching 1.5 to 4 feet (46 to 122 cm) in a season and filling a border or a generous container with ease. Most gardeners treat it as a tender perennial grown as an annual, since hard frost takes the top while the plant banks energy in fleshy, tuberous roots. Lift those roots before winter and the same plant returns to the same corner year after year.
Its one strong opinion is a wish to spread. Four o'clock drops a heavy load of seed and reseeds itself freely, an asset in a loose cottage border and something to manage in a more tailored bed. The seeds and roots are also toxic, so it is worth deciding where it may self-sow before placing it near a play area or a pet's favorite patch.
Care
The short version: four o'clock belongs in full sun with steady moisture in well-drained soil and a light monthly feed. Pinch it early for a fuller silhouette, and deadhead before the seeds drop when you want a more composed bed.
Light
Give four o'clock full sun and it rewards a sunny terrace or south-facing border with a compact shape and a heavy show of bloom. It accepts partial shade and still performs, though a dimmer corner coaxes the stems to stretch and lean, softening the tidy form a styled space wants.
Water
Keep the soil evenly moist through the season, with a closer eye during summer heat when a planting works hardest. It favors humus-rich ground that drains well and shrugs off the odd wet spell, but it should not sit in soggy soil for long.
Soil
It looks its best in well-drained, humus-rich loam, yet four o'clock obliges almost any soil a garden offers. A pH of 6.0 to 7.5 suits it, so most established beds welcome it without special preparation.
Temperature
Warmth sets the mood, roughly 50°F to 86°F (10°C to 30°C), and the plant hits its stride as summer settles in. Frost ends the top growth, which is why cooler-region gardens enjoy it as a single-season annual.
Humidity
Ordinary outdoor air is all it asks, so there is no figure to fuss over. Good spacing and airflow do more for the look, since crowded plants flop and hold dampness around the stems, undoing a clean line.
Feeding
A balanced general-purpose fertilizer about once a month through the growing season keeps the display going. A light hand suits it, because too much feed, especially nitrogen, builds weak, leggy stems that lean and snap and spoil the shape.
Pruning
Four o'clock needs little pruning, but a pinch when young shapes a fuller, more polished plant, and cutting back leggy stems restores its line. Clearing spent plants before the seeds drop keeps a bed looking intentional and its self-sowing in hand.
Size & spacing
Plants reach 1.5 to 4 feet (46 to 122 cm) tall and spread 12 to 24 inches (30 to 61 cm) wide, an easy scale for a border edge or a large pot. Give each that full spacing so the branching form has room to settle and air moves freely between plants.
When to plant
Four o'clock keeps a summer schedule and bows out at the first frost, so plan it as a warm-season flourish. Start seed indoors in late winter, or sow directly into warm soil once frost has passed. From there it carries a garden through the long evenings, blooming from midsummer to the first hard cold of fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 6 to 8 weeks before the last spring frost; soak seeds overnight to speed germination
- Plant: After all danger of frost has passed, about the same time as tomatoes
- Harvest: Summer through fall; flowers open in late afternoon or early evening and wilt by the following morning
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
For all its romance, four o'clock is an easygoing plant, and the few things that go sideways come from its own exuberance rather than pests or disease. Expect three: stems that lean, a generous return of self-sown seedlings, and seeds slow to wake. Find the look you're seeing below and the remedy is a small adjustment.
Seeds that sit and refuse to sprout
When seeds hang back, the hard seed coat is usually the reason, since it slows how fast water gets in, and cool soil only lengthens the wait. Soak them overnight or nick the coat before sowing to set them off sooner. Sow about 1/4 inch deep, hold the soil near 68°F to 70°F (20°C to 21°C), and they break ground in 5 to 7 days.
Fix:
- Soak seeds in water overnight or nick the seed coat before sowing
- Sow 1/4 inch deep and keep soil at about 68 to 70°F
Weak, brittle stems that flop over and snap
Four o'clock builds a lot of soft, branching growth quickly, and the stems can't always carry the look they create, so the plant starts to lean. Too much nitrogen or a crowded planting makes it worse, and stems snap near the base just when a bed should be at its peak. Pinch young plants for a bushier, sturdier shape, give each one room, and slip a discreet stake to the tall ones if they still sprawl.
Fix:
- Provide stakes or grow among supporting companions
- Pinch young plants to promote a bushier, sturdier habit
- Avoid over-fertilizing with high-nitrogen feeds
Volunteer seedlings popping up everywhere the next year
A single plant drops a heavy load of seed, and that vigorous self-seeding turns last season's arrangement into this year's scatter of volunteers. Deadhead the spent blooms before the seed sets to keep a planting composed, and lift young seedlings while they come away easily. In colder areas you can dig and store the tuberous roots over winter and skip the reseeding altogether.
Fix:
- Deadhead spent flowers before seeds form
- Remove volunteer seedlings while young
- Dig and store tuberous roots over winter rather than allowing reseeding
Toxicity
Beauty here comes with a caveat worth respecting. The seeds and roots are toxic to cats, dogs, horses, rabbits, livestock, and birds, and they are not safe for people, bringing on stomach pain, nausea, vomiting, and diarrhea if eaten. The seeds hold the most risk, and the roots can irritate sensitive skin, so set this plant where pets and small children cannot reach the seedpods.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Toxic
A cat that chews the seeds, roots, or foliage tends to drool, lose interest in food, and vomit. The seeds are the part most likely to cause trouble, so keep them out of reach in a household with cats.
Dogs Toxic
Dogs react much the same way, with drooling, an upset stomach, and diarrhea after eating any part of the plant. Curious chewers that dig up and gnaw the roots are most at risk, worth noting near a dog's run.
Horses Toxic
In horses the alkaloids in the seeds and roots can bring on drooling and colic, with diarrhea soon after. Keep the plant well clear of paddocks and turnout.
Rabbits Toxic
Rabbits should never nibble four o'clock, since the same toxins bring on a sore, upset gut. Never toss trimmings into a hutch or run.
Livestock Toxic
Grazing animals such as goats, sheep, and cattle can suffer stomach pain and diarrhea if they reach the foliage or dig up the roots. Fence the plant off from pasture.
Birds Toxic
For birds the seeds are the most dangerous part, and a pecked seed or chewed leaf can cause vomiting and lasting gut upset. Treat the whole plant as off-limits.
People Caution
For people the seeds and roots are toxic if eaten and cause stomach pain, nausea, vomiting, and diarrhea, so keep them away from small children who might mistake a seed for a treat. Handling the roots can also leave sensitive skin red and irritated, so wear gloves when you dig them.
Keep seeds and roots away from pets and children; wear gloves if you are sensitive when digging or handling tuberous roots.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Most four o'clocks arrive simply labeled by color, but a handful of named selections earn a place for the way they read in a planting.
'Broken Colors'
Every flower opens striped and splashed with contrasting colors, so a single plant brings a whole palette to one corner of a bed.
'Limelight'
Bright chartreuse leaves set off neon pink flowers in a pairing that carries across a garden and anchors a planting.
'Marbles' series
A mixed strain of bicolor blooms streaked and splotched in shifting color pairings, scattering variety the length of a border.
How to propagate
Bringing more four o'clock into a garden takes little effort. Sow seed for a quick first-season display, or keep a plant you have grown fond of by lifting its roots before winter.
SeedEasy
Sow indoors 6 to 8 weeks before last frost or direct sow outdoors after frost danger passes · Germinates in about 5 to 7 days at 68 to 70°F; blooms the first season
Seed is the simplest route, and it gives flowers the first summer, ideal for filling a new bed fast. Soak the seeds overnight or nick the hard coat, sow them about 1/4 inch deep, and space the seedlings 12 to 24 inches apart. Start indoors 6 to 8 weeks before your last frost, or sow straight into warm ground once frost has passed, and they sprout in about 5 to 7 days at 68°F to 70°F (20°C to 21°C).
DivisionModerate
Lift and divide tuberous roots in fall for winter storage, replanting in spring after frost · Stored tubers resprout in spring once replanted in warm soil
Where winters turn cold, a treasured plant can come back by way of its roots, much as a dahlia does. Dig the tuberous roots in fall before the first frost, brush off the soil, and store them somewhere cool, dry, and frost-free. Replant in spring once the soil warms and they resprout to take their place again.
Myths
Four o'clock is edible or harmless because it is such a common garden flower.
A familiar flower is not a safe one. The seeds and roots are toxic if eaten and bring on stomach pain, nausea, vomiting, and diarrhea, and the roots can leave sensitive skin irritated. Keep the seeds away from children and pets, and wear gloves when you handle the roots.
The flowers always open right at four o'clock.
The name is poetry, not a timetable. The blooms open in the late afternoon or early evening, cued by fading light rather than a fixed hour, and they fade by the next morning. On a cool, overcast day they may open earlier, a quiet bonus for anyone home before dusk.