Poinsettia: care, watering and how to get it to colour up again

Choosing a healthy plant, care through winter, spring pruning, summer growing and how to get a poinsettia to colour up again. Including facts about toxicity.

In short: The poinsettia (Euphorbia pulcherrima) wants a bright spot, 18–22 °C, no draughts and watering only once the surface has dried. Overwatering and cold on the way home from the shop harm it most. It colours up again if, from the end of September, it gets 14 hours of complete darkness every day for 8–10 weeks. For people and animals it is only mildly irritating, not deadly poisonous.

Latin name	Euphorbia pulcherrima, spurge family
Temperature	18–22 °C, not below 15 °C
Watering	only when the surface has dried, pour off the excess from the sleeve
Colouring up	from the end of September for 8–10 weeks, 14 h of darkness a day
Pruning	April, to 10–15 cm
Toxicity	the milky sap irritates skin, eyes and mucous membranes

The poinsettia is in fact a Mexican shrub that grows several metres tall in its homeland. The coloured "flowers" are bracts, that is, coloured upper leaves. The real flowers are tiny yellow-green structures in the middle. The plant flowers when days are short, and that is why it reaches us just before Christmas.

Most poinsettias end up in the bin in January because they drop their leaves. Usually the cause is not watering "too little or too much" but cold and draughts. Below is how to choose a healthy plant, how to handle it over winter and how to make it colour up again.

How to choose a healthy plant and bring it home

Look at the centre: the tiny yellow flowers (cyathia) should still be closed or only just starting. If they are already falling, the plant is past its peak and the bracts will soon be lost.
Leaves right down to the base: green leaves should be dense all the way down. Bare stems mean the plant has already suffered from cold or dryness.
Do not buy from the cold: poinsettias displayed by an entrance, at a market or in an outdoor stall may get a cold shock, which shows only at home.
Wrap it: even a short journey at a temperature below 10 °C is enough for it to drop its leaves within a few days. Have it wrapped in paper or film.
Compost: it must be neither waterlogged nor completely dry. Check poinsettias in a film sleeve to see whether they are standing in water.

Care over winter: light, temperature, watering

Light and temperature

Put it in the brightest place in the flat, even by a south-facing window; winter sun will not harm it. The ideal is 18–22 °C by day and not less than 15 °C at night. The leaves must not touch cold glass. A poinsettia does not tolerate a draught from an open window or door, nor hot air straight from a radiator; in both cases it drops its leaves.

Watering

Overwatering is the most common cause of death. Water only when the surface of the compost has dried and the pot is noticeably lighter, usually once a week. Use room-temperature water and after 15 minutes pour away everything that has remained in the sleeve or saucer. Complete drying out also harms it, though, showing as wilting and dropping of the lower leaves.

Feeding

Do not feed the poinsettia during flowering; it does not need it. Start feeding only in spring, when it regrows.

General advice on how to look after houseplants in the heating season is in the article How to care for houseplants in winter.

Why a poinsettia drops its leaves

Symptom	Most common cause	What to do
sudden leaf drop after purchase	cold on the way, draught	a constant warm spot, do not move it around
yellow lower leaves, wet compost	overwatering, rotting roots	let it dry out, pour off water from the sleeve
wilted plant, dry compost	drying out	immerse the pot in water for 15 min, let it drain
bracts and flowers fall	natural end of flowering (February–March) or hot dry air	further from the heating, or start spring care
sticky leaves, white flies	whitefly	yellow sticky traps, showering

What to do with a poinsettia after Christmas

A well-cared-for poinsettia keeps its bracts until February or March. After that it can be grown on as an ordinary houseplant:

March: once the bracts fall or turn green, reduce watering and let the plant rest for 3–4 weeks in mild cool at around 15 °C.
April: cut the stems to 10–15 cm above the compost. Work in gloves, as white milky sap flows from the cut. Rinse the cut surfaces on the plant with lukewarm water and the sap stops flowing.
Repotting: into a pot one size larger with well-drained houseplant compost. Resume watering.
Summer: from mid-June, when nights do not fall below 15 °C, it can be outside in partial shade. Feed every 2 weeks with houseplant fertiliser.
Pinching out: in June and again at the beginning of August pinch out the tips of the shoots. The plant branches and will have more coloured tops.
September: bring it back indoors before it cools below 15 °C.

How to get a poinsettia to colour up again

The bracts colour up only if the plant gets long nights for several weeks. A single lamp switched on in the evening is enough to stop the process, however. The procedure:

Start at the end of September or the beginning of October if you want colour for Christmas.
Every day put it for 14 hours in complete darkness, for example from 6 pm to 8 am in a cupboard, an unused pantry or under an opaque box. Even weak light from the street or the fridge interferes.
In the daytime return it to a bright window so that it has 10 hours of light.
Keep the temperature at 18–20 °C, water sparingly and feed more weakly.
Continue for 8–10 weeks, until the bracts are fully coloured. After that ordinary placement is enough.

Poinsettias grown at home tend to be taller and sparser than those from the shop, as professional growers use products against stretching. The usual result is still a pretty plant with several coloured tops.

Is the poinsettia poisonous?

The poinsettia does not deserve its reputation as a deadly poisonous plant. A large American study processed 22,793 cases in which a person, most often a small child, came into contact with a poinsettia. Nobody died, 92.4% of people had no symptoms at all and 96.1% did not need medical treatment.

The same holds for animals. The American ASPCA states that the poinsettia irritates the mouth and stomach and sometimes causes vomiting, but that its toxicity is "generally overrated". According to the Pet Poison Helpline it is only mildly toxic to dogs and cats, and symptoms such as drooling, vomiting or, rarely, diarrhoea usually pass on their own.

Caution is nevertheless in order:

The white milky sap contains irritant substances. On the skin it can cause redness and itching, so wear gloves when cutting and repotting.
The sap must not get into the eyes. If it does, rinse the eye thoroughly with water at once and see a doctor if burning persists.
Put the plant out of reach of cats and small children, more because of stomach upset and a broken pot.
If you suspect a child has swallowed some, call the Toxicology Information Centre: 224 919 293 or 224 915 402. For an animal, call a vet.

Much more dangerous are other houseplants and garden plants; you will find an overview in the article Poisonous ornamental plants. Other Christmas flowers, such as the Christmas cactus or the cyclamen, are covered in the article Christmas flowers and how to grow them.

Frequently asked questions

Is a poinsettia poisonous to cats?

Only mildly. The milky sap irritates the mouth and stomach and can cause drooling or vomiting, which usually passes on its own. Fatal poisonings are not documented, but still keep it out of a cat's reach.

Why is my poinsettia dropping its leaves?

Most often because of cold on the way from the shop, a draught or overwatering. It naturally loses its bracts in February to March, when flowering ends.

How often should I water a poinsettia?

Only when the surface of the compost has dried, usually once a week. Pour away excess water from the sleeve or saucer after 15 minutes.

How do I get a poinsettia to turn red again?

From the end of September give it for 8–10 weeks every day 14 hours of complete darkness and 10 hours of light at 18–20 °C. The colour appears gradually on the new top leaves.

Can a poinsettia go outside in summer?

Yes, from mid-June to September, when nights do not fall below 15 °C. Put it in partial shade, water regularly and feed.

What temperature does a poinsettia need?

Ideally 18–22 °C, at night not less than 15 °C. Below 10 °C, even briefly, it gets a cold shock and drops its leaves.

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 data from specialist literature and official sources, which we cite in every article.