Germination temperature
About 20-21 °C (68-70 °F).
Flower growing guide
Four o'clock, or marvel of Peru, opens its fragrant trumpet flowers in the late afternoon and evening. The large seeds sprout in 5-7 days in warmth, and in frost-free climates the plants return each year from tuberous roots.
About 20-21 °C (68-70 °F).
About 6 mm (1/4 in), covered.
5-7 days.
Darkness: cover the seed.
Optional overnight soak or a small nick in the seed coat to speed germination.
Both work; start indoors 6-8 weeks before planting out, or sow directly after the weather warms.
The seeds are large, black and wrinkled, so they are easy to space individually. Seeds and roots are toxic if eaten: keep the packet away from children and pets, and wash your hands after handling.
Optional. Nicking the hard seed coat with a nail file is an alternative to soaking (University of Wisconsin-Madison). Do not cut into the inner seed.
Not needed. Four o'clock is a warm-climate plant from Mexico and Central America with no cold requirement.
Recommended. Soaking the seeds in water overnight speeds germination (NC State Extension; University of Wisconsin-Madison). Sow them straight after soaking.
Iowa State University gives 21 °C (70 °F); the University of Wisconsin-Madison gives 20-21 °C (68-70 °F). Germination is slow in cold soil.
Cover with about 6 mm (1/4 in) of soil or seed compost (University of Wisconsin-Madison).
Almost any soil works; humus-rich, well-drained soil gives the best plants.
Keep the soil evenly moist but not waterlogged until seedlings emerge.
Four o'clock germinates in darkness (Iowa State University), so make sure every seed is covered.
Usually 5-7 days at 20-21 °C (68-70 °F).
Sow in pots 6-8 weeks before planting out (Iowa State University). Move plants outside once there is no risk of frost, at about the same time as tomatoes. Plants quickly form a long taproot, so use deep pots and do not leave them in pots too long.
Space plants 30-60 cm (12-24 in) apart. Planted closely, they form a dense flowering hedge.
Young plants need little care beyond watering in dry weather. They grow into bushy plants about 60-90 cm (2-3 ft) tall, sometimes up to 1.2 m (4 ft).
Cause: hard seed coat or cold soil. Fix: soak the seeds overnight or nick the coat, and sow when the soil is warm.
Cause: weak, brittle stems. Fix: plant in a sheltered spot, plant closer together, or give light support.
Cause: four o'clock self-seeds vigorously and can become weedy. Fix: pull unwanted seedlings while small and collect seeds before they drop.
Cause: handling the roots can cause contact dermatitis in sensitive people. Fix: wear gloves when digging tubers or pulling plants.
Flowers open late in the day and many are strongly sweet-scented, attracting night-flying moths. Plant them by a patio, door or window.
In frost-free areas, including most of the Indian plains, plants grow back each year from tuberous roots. Sow seed as the weather warms; plants flower through the hot season and the rains.
In cold climates or high hills, dig the tubers before the first frost, shake off the soil and store them dry, cool and frost-free until spring, like dahlias (University of Wisconsin-Madison).
One plant can carry flowers of several colours, striped or splashed, so a mix gives a varied display.
Seeds and roots are toxic if eaten, causing stomach pain, nausea, vomiting and diarrhoea (NC State Extension). Avoid planting where small children play and never let anyone eat the seeds.
Sow four o'clocks for easy, colourful flowers that open and scent the garden every evening.
Yes, it helps. Soak them in water overnight, or nick the hard coat, then sow 6 mm deep in warm soil. They usually sprout in 5-7 days.
Yes. The seeds and roots are toxic if eaten and the roots can irritate sensitive skin. Store seeds safely, wash your hands after sowing, and wear gloves when digging the tubers.
That is normal. The flowers open in the late afternoon or evening and close the next morning; on cloudy days they may open earlier.
In frost-free climates it is a perennial that regrows from its tuberous roots and also self-seeds. Where the ground freezes, lift and store the tubers or sow fresh seed each year.