Poinsettia care guide

Cold is the biggest risk on the way home. Even a few minutes of frost can blacken the leaves, and that damage cannot be undone, so carry it wrapped and take it out of its paper or plastic sleeve as soon as you are inside. Cutting the sleeve open is gentler than pulling it up over the bracts.

Give it the brightest spot you have, close to an east, west or south-east window, at 15 to 21 °C (59⁠–⁠70 °F). Keep the leaves off cold glass and away from radiators, heating vents and doors that open onto winter air.

Most poinsettias come in a decorative foil or a pot cover without holes, and water that collects there keeps the roots wet until they rot. Lift the plant out to water it at the sink, let it drain and empty the foil before you put it back, or cut holes in the bottom of the foil.

Then feel the soil. If the top 2.5 cm (1 in) is dry, water until it runs out of the bottom. If it is still damp, check again in a couple of days.

The small yellow buttons in the middle are the true flowers. Over the weeks they open, shed pollen and fall off. That is normal aging, and the colored bracts stay on long after. Leaves that drop in the first days usually point to a cold trip home, a draft or wet roots, so check those first.

Getting it to color again

A poinsettia colors up only after weeks of long nights. To get color by December, give it 14 hours of complete darkness every night from about 1 October, for example from 17:00 to 08:00 in a closet or under a cardboard box, and bring it back into bright light every morning so it gets 6 to 10 hours of light a day.

Keep nights around 16 to 18 °C (61⁠–⁠64 °F) and keep feeding every two weeks. Do not switch on a lamp or open the closet during the dark hours, because even a short spell of light can delay the color. The bracts start to color after about 6 to 8 weeks. Stop the dark routine once they are fully colored, usually in early December.

After Christmas, a plant that keeps its leaves gets the same bright spot and careful watering until spring. If it drops most of them, let it rest somewhere cool, about 10 to 13 °C (50⁠–⁠55 °F), and water only enough to stop the stems shriveling. In March or April, cut the stems back to 10 to 15 cm (wear gloves, the milky sap can irritate skin), repot one size up if roots fill the pot, and start feeding. From June it can stand outside once nights stay above about 16 °C (61 °F). Bring it back in by mid-September.

Check the soil every few days. When the top 2.5 to 5 cm (1 to 2 in) feels dry, water until it runs out of the bottom, then empty the saucer. In Botanicaly’s plant data that is about every 7 days in summer and every 10 days in winter, but the soil decides.

Take the plant out of its foil or plastic sleeve to water it, or cut holes in the bottom. Water that collects in the sleeve keeps the roots wet and leads to root rot.

Place a poinsettia in the brightest spot you have, close to an east, west or south-east window. Keep the leaves off cold glass and away from doors that open onto winter air.

Do not feed a poinsettia while it is in color. Once the bracts fade and new growth starts in spring, give a balanced liquid fertilizer every two weeks at half strength, and keep going through summer and the autumn dark weeks.

Keep it at 15 to 21 °C (60 to 70 °F), with no cold drafts and no heat from radiators. Below about 10 °C (50 °F) it can suffer chilling damage and drop leaves. Frost or a long spell of cold can kill it, and even a few minutes of frost on the way home can blacken the leaves.

Ordinary room humidity suits a poinsettia. Keep it away from radiators and heating vents, because warm, dry air makes the leaves drop. Do not mist it: wet bracts can get gray mold.

Cold is the most common cause: a cold trip home, a draft, temperatures below about 10 °C (50 °F) or leaves touching a cold window. Wet soil from water standing in the foil sleeve, dry soil and warm air from a heater also make leaves drop. Check what changed in the last few days and fix that first.

If the leaves and bracts wilt and turn black, it was frost or cold, and that damage cannot be undone. A few leaves falling in late winter is normal as the plant slows down. If it drops most of them, let it rest somewhere cool, about 10 to 13 °C (50⁠–⁠55 °F), with just enough water to keep the stems firm.

Sooner or later the bracts fade or turn greenish, the yellow buttons fall and the plant may drop leaves as it slows down in late winter. That is the end of its display, not a disease.

Many people compost it at this point, and that is fine. If you want to keep it, follow the after-Christmas steps in “Getting it to color again”: a cool rest if it drops most of its leaves, a cutback in March or April and regular feeding through summer.

Do not expect color again in a few weeks. The bracts only color after about 6 to 8 weeks of long, dark nights from about 1 October, so a kept plant colors again the next December at the earliest.