How to Grow Four O'Clock Flower (Bunga Pukul Empat) in Malaysia

Yes, four o'clock flower (Mirabilis jalapa, bunga pukul empat) is one of the easiest flowers you can grow in lowland Malaysia. It loves heat, shrugs off rain better than most annuals and often self-seeds around old kampung gardens. From seed it usually starts flowering in about 2–3 months, opening fresh trumpet flowers every late afternoon. The one thing you must know first: the seeds and roots are poisonous if eaten. Grow it where small children and pets will not chew the black seeds, and never mix it into an edible garden bed where it could be mistaken for a food plant.

Quick facts

Item	Four o'clock flower
Sun	Full sun to part shade; flowers best with 4–6 hours of sun
Sowing depth	1–2 cm; soaking seeds overnight speeds germination
Germination	5–14 days
Spacing	45–60 cm; one plant per large pot
Days to flower	About 60–90 days from sowing
Container	25–30 cm pot or polybag (10 L or more)
Support	Not needed; trim if it sprawls

Safety first

All parts of four o'clock should be treated as not edible. The seeds and the thick roots are the most toxic and can cause vomiting, stomach pain and diarrhoea if swallowed. The sap may irritate sensitive skin, so wear gloves if you are pulling out plants or handling roots.

• Plant it away from where toddlers play, and collect or remove ripe black seeds if young children visit.
• Keep seed packets out of reach.
• Do not grow it in the same container as vegetables or herbs.
• If someone swallows seeds or root, seek medical advice promptly.

Choosing a spot and container

Four o'clock is a bushy plant that grows about 60–90 cm tall and wide in a season, and it forms a thick tuberous root underneath. In the ground it is close to indestructible. In pots, give it a 25–30 cm pot or a 10 L or larger polybag per plant so the root has room.

It flowers best in full sun but copes with part shade, so it suits a terrace-house front yard, the corner of a porch or a sunny balcony. Because the flowers open late in the day and are fragrant, a spot near a window or sitting area where you are home in the evening lets you enjoy them most.

Soil and potting mix

It is not fussy. Any reasonably drained garden soil or potting mix works. For pots, a simple mix is:

• 2 parts potting mix or garden soil
• 1 part compost
• A handful of burnt rice husk (sekam bakar) for drainage

Very rich soil makes lots of leaves and fewer flowers, so do not overdo manure.

How to sow four o'clock step by step

1. Soak the seeds. The seeds are black, wrinkled and about the size of a peppercorn. Soak them in room-temperature water for 8–12 hours.
2. Prepare pots filled with moist mix, or small cups if you prefer to transplant later.
3. Sow 2 seeds per spot, 1–2 cm deep, and cover.
4. Water gently and keep moist but not soggy.
5. Wait 5–14 days for seedlings. They come up with two broad seed leaves.
6. Thin to the strongest seedling per pot when they have 2–3 true leaves.
7. Wash your hands after handling the seeds, and put leftovers away safely.

New to sowing? The step-by-step basics are here:

GuidesHow to Start Vegetable Seeds at Home (Beginner's Guide for Malaysia)Sow vegetable seeds in trays at home - the right mix, sowing depth, watering, light, preventing damping-off, hardening off and transplanting.

Transplanting and shaping

If you started seeds in cups, plant them out at 3–4 weeks, before the tuberous root starts to thicken. Plant at the same depth and water well.

Four o'clock needs no staking. If it gets too wide for your space, trim stems back by a third after a flush of flowers; it regrows quickly. Pinching the tips of young plants once makes them bushier.

Watering in hot and rainy weather

• Hot spells: water in the morning when the top few centimetres of soil are dry. Established plants in the ground cope with short dry periods, and leaves may droop at midday and recover by evening.
• Rainy season: four o'clock handles rain well, but potted plants still need drainage. Empty saucers so the root does not sit in water.
• Water at the base. Constantly wet leaves in humid weather can lead to leaf spot.

Feeding

Little feeding is needed. Mix compost into the soil at planting and add a thin layer of compost on top every couple of months. If growth looks pale, give a diluted liquid feed once or twice. Heavy feeding produces big leafy plants with fewer flowers.

To mix liquid fertilizer at the right strength:

CalculatorsFertilizer Dilution CalculatorFertilizer dilution calculator: how many ml or grams of liquid or soluble fertilizer to mix for your watering can or sprayer, from ml/L or 1:N ratio.

Flowering, colours and seed

The flowers open in the late afternoon, which gives the plant its name, and close again the next morning. They are sweetly scented in the evening and visited by moths. One plant may carry flowers of several colours, or flowers that are striped or splashed, such as magenta, yellow, white and pink, on the same bush.

You do not need to deadhead, as the plant keeps flowering for months. After flowering, round black seeds form and drop to the ground, where many will sprout. That is handy if you want more plants, but it can make four o'clock weedy. Pull unwanted seedlings while they are small, and pick off ripe seeds if you have young children around.

In Malaysia the plant often lives on for years, growing back from its tuberous root. If an old plant becomes woody and tired, cut it back hard or replace it with fresh seedlings.

Common pests and diseases in Malaysia

Four o'clock is tough and has few serious problems.

• Aphids and whiteflies. On new shoots and leaf undersides. Spray off with water, or use diluted neem oil in the evening.
• Caterpillars. Occasional holes in leaves. Hand-pick.
• Snails and slugs. Can chew young seedlings after rain. Pick off at night.
• Leaf spot and mildew. In crowded, humid spots. Thin stems, remove affected leaves and improve airflow.
• Root rot. Only in waterlogged pots. Improve drainage.

For gentle organic fixes:

GuidesOrganic Pest Control for Malaysian Home GardensIdentify aphids, whiteflies, mealybugs, thrips, spider mites, caterpillars, leaf miners, snails and fruit flies, and control them organically and safely.

FAQ

Why are my four o'clock flowers closed? They are closed for most of the day by design. They open from late afternoon, and on cloudy days may open a little earlier. Check in the evening.

Is four o'clock safe to grow with children or pets? It can be, with care. The seeds and roots are toxic if eaten, so plant it away from play areas, remove ripe seeds and teach children not to eat garden seeds.

Can I grow four o'clock from the root? Yes. The tuberous root can be dug up and replanted, and it will sprout again. Wear gloves when handling it.

Will it take over my garden? It can spread by dropped seed. Pull seedlings you do not want, or collect seeds before they fall.

For more ideas on growing in small spaces, see:

GuidesBalcony Vegetable Garden in Malaysia - A Beginner's GuideGrow vegetables on a condo or apartment balcony in Malaysia - sun by direction, wind, weight, containers, easy first crops, watering and building rules.