Osteospermum: growing African daisies, sowing and overwintering

How to grow osteospermum from seed, young plants or cuttings, why it takes a break in the heat and how to keep it under cover over winter.

In brief: Osteospermum (African daisy) wants full sun, a free-draining substrate and rather dry than wet. It goes outdoors after the last frosts, flowers from spring until the first frosts and often takes a break in the heat. It does not tolerate frost: for winter move it into the light at 5–10 °C or take cuttings in August. From seed it is sown in February to March.

Latin name	Osteospermum, Asteraceae
Height	20–50 cm depending on variety
Position	full sun, sheltered from wind
Sowing	February–March indoors, roughly 18–21 °C
Outdoors	after the last frosts, usually from mid May
Overwintering	bright room 5–10 °C, or cuttings in August

Osteospermum is one of the most reliable plants for window boxes and containers on a sunny balcony. It has daisy-like flowers in white, yellow, orange, pink and violet, often with a dark centre, and flowers from May until autumn. It comes from southern Africa, hence the English names African daisy and Cape daisy.

In garden centres it is sold mainly as a ready-grown young plant in spring. Anyone who can overwinter the plant or multiply it from cuttings, however, does not have to buy it again every year. And anyone who likes sowing can also raise it from seed.

Osteospermum, Dimorphotheca or marguerite?

Under the label "African daisy" two different plants meet in shops. Osteospermum is a perennial herb to subshrub, grown here as an annual or as an overwintered plant in a container. Dimorphotheca is annual, lower and sown straight outdoors in spring. Both have similar flowers and both want sun.

With the native daisies, osteospermum shares only the family. Our ox-eye daisy (Leucanthemum) is a frost-hardy perennial for beds; we write about it in the article flowering daisy brightens the garden.

Young plants, cuttings or seed

Route	When	Advantages	Disadvantages
bought young plant	April–May	flowers at once, exact variety and colour	buying again every year
cuttings from your own plant	end of spring or August	an exact copy of the parent plant, little space needed over winter	you need a bright cool place
sowing seed	February–March	cheap, plenty of plants	narrower choice of varieties, colours from mixes may vary

Most modern balcony varieties are propagated only vegetatively, that is by cuttings. From seed mainly seed-merchant mixes are grown, which flower a little later but well.

Sowing step by step

Sow from February to mid March, so that the plants are strong in May.
Fill a seed tray or bowl with fine seed compost and moisten it.
Space the seeds 2–3 cm apart and cover them with a thin layer of substrate.
Put them in a bright place at roughly 18–21 °C and keep them lightly moist, ideally under a lid or film.
After emergence remove the lid and move the seedlings to a cooler and as bright a place as possible, otherwise they become leggy.
When they have two to three true leaves, prick them out singly into cups or tray cells.
Pinch out young plants above the third or fourth leaf; they branch better.
From the beginning of May harden them off and plant them out after the last frosts.

What else is worth sowing on a windowsill in February is summarised in the article what to sow in February.

Balcony and bed: light, substrate, watering

Osteospermum needs as much sun as possible. In shade it flowers little, the plants become leggy and in older varieties the flowers stay closed. It suits a south- or west-facing balcony, a sunny rock garden bed and containers on a terrace. You can find combinations with other drought-loving balcony plants in the article balcony plants that will flower until autumn.

The substrate should be light and free-draining. Mix a handful of perlite or sand into ordinary substrate for balcony plants and do not forget drainage holes. Leave a spacing of roughly 20–25 cm in a window box and 25–30 cm in a bed.

Water once the surface of the substrate has dried. Osteospermum tolerates a short drought, but not permanent overwatering: the roots rot and the plant wilts even in wet soil. From June feed once every two weeks with a fertiliser for balcony plants with a higher potassium content and only a little nitrogen.

Why the flowers close and why it does not flower in summer

Two things surprise almost everyone who grows osteospermum for the first time.

Closed flowers. Older varieties close their flowers at night and in overcast weather. It is not a disease. Newer varieties have flowers open even in shade or in dull weather.
A summer break. In heatwaves many varieties stop setting buds and only grow. When it cools in August they flower again. Do not overdo watering at that time and feed less.
Spent flowers. Remove them regularly together with the stalk. The plant then does not make seed and forms new buds faster.
Leggy plants. Too much nitrogen and too little light give long soft stems. Cut them back by a third and move the container into the sun.

Among pests aphids appear, mainly on young shoots. With overwatering there is a risk of fungal root diseases, against which mainly a free-draining substrate helps.

Overwintering: the plant or cuttings

Most varieties do not tolerate frost. According to the RHS even the hardier Osteospermum jucundum is rated H3, that is suitable for overwintering outdoors only in mild coastal areas. In the Czech Republic, therefore, count on overwintering under cover.

Overwintering the whole plant

Before the first frost, usually in October, bring the container indoors.
Cut the plant back by roughly a third to a half and remove the remains of flowers.
Place it in a bright place at a temperature of around 5–10 °C, for example on a cool staircase or in a conservatory.
Water little, just so that the substrate does not dry out completely. Do not feed.
In March repot it into fresh substrate, gradually water more and put it outdoors after the last frosts.

General principles for plants overwintered in a flat can be found in the article overwintering houseplants.

Cuttings: less space, young plants

The RHS recommends propagating osteospermum by softwood cuttings at the end of spring or semi-ripe cuttings at the end of summer. In practice August is the most convenient. Cut shoot tips 5–8 cm long without flowers, remove the lower leaves, dip the cut in rooting stimulant and push the cuttings into moist seed compost with perlite. Under a transparent cover in the light without direct sun they usually root within a few weeks. The young plants then overwinter on a windowsill in a cooler room, and in spring you have them for free.

Frequently asked questions

Is osteospermum a perennial?

Botanically yes, but in the Czech Republic it usually does not survive frost. It is therefore grown as an annual, or moved for winter into a bright room at 5–10 °C.

Why does my osteospermum not flower?

Most often it has too little sun, is in summer heat or gets too much nitrogen. In heat flowering naturally pauses, and at the end of summer it sets buds again. Regularly removing spent flowers also helps.

When should I sow osteospermum?

From February to mid March indoors at a temperature of roughly 18–21 °C. Plant it out only after the last frosts, usually from mid May.

How do I overwinter osteospermum?

Before frost bring the plant indoors, cut it back and leave it in the light at 5–10 °C with minimal watering. Instead of the whole plant you can take cuttings in August and overwinter only the young plants.

Why do osteospermum flowers close?

Older varieties close their flowers at night, in shade and in overcast weather. It is natural behaviour, not a disease. Newer varieties stay open even in poorer light.

Sources

Updated: 27 September 2026

Author: Jana Vránová, the editorial name of the Pěstík.cz team. She writes about the garden, herbs and essential oils. We take safety and dosage information from specialist literature and official sources, which we cite in every article.