Four o'clock flower: colourful evening blooms in 60 days

Many amateur gardeners want precisely the same thing in spring: plenty of colour in a short time, minimal effort and, ideally, a plant that does not wilt by midday. A species that truly comes into its own in the evening is an ideal addition to that wish list. One surprisingly resilient night-flowering plant fits the bill perfectly, yet remains something of an insider tip in British gardens.

The quiet queen of the evening

This plant is the four o'clock flower, botanically known as Mirabilis jalapa. Originally from South America, it is grown here as a fast-growing tuberous plant. Over the course of summer, it develops dense, bushy clumps around 40 to 80 centimetres high.

Its soft, light-green leaves and countless trumpet-shaped flowers are distinctive. The blooms measure roughly three to five centimetres across and come in a broad range of colours:

• pure white or vibrant yellow
• shades of pink and red
• violet
• bicoloured or speckled forms
• sometimes even several colours on one single plant

The real attraction is that its flowers do not open until late afternoon, closing again in the morning. Just as many other perennials have faded or disappeared into shaded areas, the four o'clock flower begins its display.

“Anyone sitting in the garden after work gets a daily evening show from this night flower – complete with a delicate fragrance.”

Just 60 days to a colourful display

For impatient gardeners, its speed is perhaps the most appealing feature. The four o'clock flower is among the perennials that establish themselves exceptionally quickly. On average, just one to two months pass between sowing in spring and the first flowers appearing.

The approximate timetable is as follows:

• Spring: sow or plant after the last frosts
• 7–10 days: seeds germinate
• about 60 days: flowering begins
• flowering period: from late spring until the first harder frosts

This makes the plant ideal for quickly filling bare areas in a border, or for turning window boxes and containers into a sea of evening flowers within a single season.

Starting four o'clock flowers in spring

If you are planting four o'clock flowers in spring, timing deserves a little attention. The key is to wait until frosts have passed and the soil has retained some warmth. There are two options.

Raising plants indoors

To gain a head start, sow on a windowsill or in a greenhouse six to eight weeks before the last expected frost. A practical method is to:

• fill small pots with loose, free-draining seed compost
• soak the fairly hard seed coat in water overnight
• press the seeds around 1.5 centimetres deep into the compost
• water gently and keep the compost evenly moist
• aim for a temperature between 18 and 20 degrees

In these conditions, seedlings usually emerge after a little over a week. Once the plants are sturdy enough and there is no longer any risk of frost outdoors, they can be moved into a border or a larger container.

Sowing directly in borders or containers

For the simplest approach, wait until the soil has warmed properly in spring. The seeds can then be sown directly where they are to grow permanently. Choose a sunny position that does not remain waterlogged.

Site requirement	Recommendation
Light	at least 6 hours of sun each day
Soil	nutrient-rich, loose and well drained
Water	about 2.5 cm per week, with no waterlogging
Container size	30–40 cm deep, including a drainage layer

For containers, a blend of garden soil and multipurpose compost works well. A layer of expanded clay or gravel in the base of the pot prevents waterlogging, which the tubers strongly dislike.

Care: remarkably straightforward

Once the four o'clock flower has rooted in, it proves far tougher than its delicate appearance suggests. It tolerates heat fairly well, copes with occasional dry periods and is considered largely resistant to diseases and pests.

The main care points are:

• water regularly but moderately, especially when growing in containers
• apply a little liquid fertiliser for flowering plants every two to three weeks in summer
• remove some faded stems to limit self-seeding
• support plants in strong winds if they become particularly tall

“In areas with mild winters, the tubers become stronger in the ground year after year – turning a quick seasonal flower into a genuine long-term resident.”

Overwintering and controlling vigorous growth

In warmer locations, the plant often survives light frosts in the border, with the tubers sprouting again the following spring. In regions with harsh winters, it behaves more like an annual summer flower unless you give it a little help.

Lifting and storing the tubers

Once the first hard frost has damaged the growth above ground, cut the plant back and carefully lift the tubers using a garden fork. Then:

• leave them to dry for several days in an airy place
• gently brush away any remaining soil
• store them in boxes with lightly dry growing medium or newspaper, somewhere cool and frost-free

The tubers can be replanted in the garden or in pots the following spring. Over time, this creates a real supply of night-flowering plants.

Managing self-seeding

The four o'clock flower produces abundant seed and readily self-seeds in open borders. This can be welcome if you enjoy natural-looking, slightly wild garden scenes. Anyone who prefers a tidier look, or has young children, should remove some faded sections before seeds can form.

There is another consideration: the whole plant is regarded as poisonous if eaten, particularly the tubers. In family gardens, it is therefore best planted where young children and pets cannot constantly reach it.

Where the four o'clock flower makes the biggest impact

In everyday garden planting, this night flower shows its strengths best when positioned with care. Effective places include:

• along the edge of a patio or beside a seating area, where its evening scent can be enjoyed
• combined with day-flowering plants that take centre stage in the morning and at midday
• in front of relatively plain shrubs, allowing the colours to stand out in the evening
• in a large container on a balcony or roof terrace, where it faces little competition

Mixed plantings with ornamental grasses, low roses or sage are especially attractive. While these companions provide interest during the day, the night flowers take over from late afternoon.

Useful practical details

The name “night flower” is slightly misleading, as the blooms often open in late afternoon, when the sun is no longer so intense. Many insect species, including moths, then find a valuable food source. This perennial is therefore a sound choice for anyone wishing to support biodiversity.

Gardeners who enjoy experimenting can make the most of its colour diversity. As different colour forms can appear on one plant, unexpected combinations occur again and again. Children in particular are often fascinated by these “whims” of nature – provided they understand that no part of the plants should be put in their mouths.

Anyone looking for an undemanding yet striking addition to an existing perennial border should give the four o'clock flower a try next spring. With a few seeds or tubers, a sunny spot and some water, a previously dull corner of the garden can become an evening stage within 60 days – without hours of maintenance or expensive specialist tricks.