Growing and caring for poinsettia
- Poinsettias bloom when the days get shorter.
- The colorful “flowers” of poinsettias are actually modified leaves called “bracts.”
- Poinsettias grow well in moist soil and temperatures between 65 and 70 degrees F.
- They can be grown outdoors during summer.
- Poinsettias are not poisonous, but the sap may cause dermatitis.
Native to Mexico, poinsettias are in the Euphorbia family and are a popular holiday plant because of their colorful bracts (leaves). There is also a species that is used as a cut flower. They are most commonly used for decorating during the winter holidays, but are also attractive as green plants throughout the year.
Poinsettias change color in response to shorter winter days. Poinsettia flowers are actually made up of the bracts, which look like petals, and the tiny yellow flowers in the center, called cyathia. The colorful bracts attract insects to the flowers and will drop after pollination.
Poinsettias are not harmful to animal or human health. But they should not be eaten.
- The sticky white sap can cause a skin rash, so gloves are recommended when working with these plants.
- Avoid contact with eyes and mouth.
- Wash tools well after use as the sap can make tools sticky.
Poinsettias come in many colors
You can find poinsettias around the holidays to fit into almost any decorative scheme. They range from creamy white to pink to the traditional bright red. Some varieties have bracts with patterns in red and white, pink and white, or green and white and even bright orange.
Flower forms vary as well with some looking similar to a rose. You will also find unusually colored poinsettias such as blue or purple in garden centers. These are cream-colored varieties that are spray painted. They are sometimes sprinkled with glitter.
- Indoor light: Put in a south, east or west window where the plant will receive bright daylight.
- Outdoor light: Part sun, 4 to 6 hours daily.
- Indoor temperatures of 65-70 degrees F is ideal.
- Avoid placing poinsettias where temperature fluctuates or may be drying, such as near cold drafts, heat ducts, fireplaces, fans, space heaters, etc.
- Poinsettias will suffer damage if they are exposed to temperatures below 50 degrees F.
- Freezing temperatures will kill poinsettias.
- Keep soil moist.
- Water plant when the soil surface feels dry to a light touch, or pot feels lightweight when lifted. Never allow poinsettias to get so dry that they wilt.
- Remove from decorative foil or outer pot before watering.
- Make sure your plant is in a pot that drains freely.
- Set plant in a sink and water thoroughly, allowing the plant to drain completely.
- Never allow poinsettia pots to sit in excess water. Constant wetness will rot plant roots.
- Continue watering as needed January through March.
- You do not need to fertilize your poinsettia during the holidays.
- Start fertilizing your plant when you see new growth (new green leaves, stems, bracts).
- Fertilize with an all-purpose household plant fertilizer.
- Mix with water it at half the recommended strength.
- Feed your poinsettia every 3-4 weeks to keep plant healthy and provide the necessary nutrients for new growth.
In late spring or early summer, transplant your poinsettia into a larger container (about 2 to 4 inches bigger than the original pot) or into a part-sun garden bed.
- In pots, use a soil mix with a good amount of organic matter such as peat moss. Make sure your new pot has good drainage.
- In the garden, plant into a garden bed with well-drained soil that gets 4 to 5 hours of sun per day. Mix in organic matter such as peat moss or compost into the soil. This will help maintain soil moisture and create a good growing environment for the roots.
- Water your poinsettia thoroughly after transplanting.
“How can I make my poinsettia rebloom?” is a common question.
Poinsettias can be grown as attractive green plants, but most people are interested in making their green poinsettia colorful again and ready for the holidays.
It is not an easy task, as it requires excluding light from the plant for a period of time while keeping the plant healthy. The reduction in light prevents the plant from producing chlorophyll, the pigment that makes plant parts green. This changes the bracts to red, pink or white, depending on the poinsettia variety.
Dr. Leonard Perry, Extension professor emeritus at the University of Vermont and author of Caring for Your Poinsettia Year-Round, developed an easy-to-follow poinsettia care calendar based on the holidays of the year.
New Year's Day
- Fertilize if you see new growth.
- Continue to provide adequate light and water for prolonged bloom for several weeks.
- Check your plant for signs of insects, such as white fly, and manage them if you find them. See Managing insects on indoor plants.
- If your plant has become long and leggy, cut back to about five inches tall to promote more compact growth.
St. Patrick's Day
- Prune off faded and dried parts of the plant.
- Remove leaves from the soil surface, and add a little more potting soil if the roots are visible.
- Continue keeping the plant in a bright, sunny window.
- Trim off two to three inches of branches to promote side branching.
- If you plan to continue growing your poinsettia as a potted plant, transplant into a container.
- Move the plant outside for the summer and place in indirect light.
- You can also transplant it directly into your garden.
Fourth of July
- Trim the plant again.
- Move it into full sun.
- Continue to water and fertilize but increase the amount to accelerate growth.
- Move indoors to a spot that gets at least six hours of direct light daily, preferably more.
- As new growth begins, reduce the fertilizer to one-quarter the recommended strength.
- Starting on or near Sept. 21, give the plant 16 hours of uninterrupted darkness (put the plant in a closet, basement or under a box) and 8 hours of bright light every day. Note that during the dark period, the plant cannot receive even the slightest bit of light at any time.
- Maintain night temperatures in the low 60 degrees F range.
- Continue to water and fertilize at the reduced rate.
- Rotate the plant daily to give all sides even light.
- Discontinue the short day/long night treatment.
- Put the plant in a sunny area that gets at least six hours of direct light.
- Reduce water and fertilizer.
Enjoy your "new" poinsettia. Start the cycle all over again after the new year.
Neil O. Anderson, professor of horticultural science, UMN College of Food, Agricultural and Natural Resource Sciences, and Leonard Perry, Extension professor, University of Vermont reviewed this content.
Reviewed in 2020