Colorful poinsettias are America’s favorite flower for the year-end holidays. Poinsettias rank as the nation’s top selling potted flowering plant, and more than 61 million poinsettias are sold each year in this country. Poinsettias represent over 85 percent of the potted plant sales during the holiday season, and are commercially grown in all 50 states. California is the top poinsettia producing state. $220 million worth of poinsettias are sold during the holiday season.

Red has continued to be the popular color with Freedom Red and other red-colored poinsettias making up nearly 75 percent of the inventory. The remaining 25 percent was divided among other cultivars. Other colors include nearly white, medium pink and red with pink flecks. There are over 100 cultivars of poinsettias available.

The poinsettia (Euphorbia pulcherima) was cultivated by the Aztecs of Mexico. Poinsettias were first introduced into the United States in 1825 by Joel Robert Poinsett. While serving as the first U.S. ambassador to Mexico, he visited Taxco and found the plants growing on adjacent hillsides. Poinsett, a botanist, had some plants sent to his home in Greenville, South Carolina. After supplying his own greenhouses, Poinsett distributed plants to various botanical gardens and to some horticultural friends.

The showy colored parts of poinsettias that most people think are the flowers are actually colored bracts (modified leaves). The flowers or cyathia are in the center of the colorful bracts.

Poinsettias are traditional Christmas plants that will last through the holiday season and beyond. When selecting the best plant for your home environment, consider the following:

• Choose a plant with dark green foliage down to the soil line.
(Cultivars with lighter colored or mottled bracts typically have lighter green foliage)

• Choose bracts that are completely colored.

• Do not purchase poinsettias with a lot of green around the bract edges.

• Do not select plants with fallen or yellowed leaves.

• The poinsettia should look full, balanced and attractive from all sides.

• The plant should be 2 1/2 times taller than the diameter of the container.

• Choose plants that are not drooping or wilting.

• Do not purchase plants that are displayed in paper or plastic sleeves. Plants held in sleeves will deteriorate quickly.

• Do not purchase plants that have been displayed or crowded close together. Crowding can cause premature bract loss.

• Check the plant’s soil—if the soil is wet and the plant is wilted, this could be an indication of root rot.

• Evaluate the poinsettia’s maturity. Check the true flowers which are located at the base of the colored bracts. If the flowers are green or red-tipped and fresh looking, the bloom will “hold” longer than if yellow pollen is covering the flowers.

• When you take the poinsettia home, be sure to have it sleeved or covered when outdoor temperatures are below 50 degrees F.

The length of time your poinsettia will flourish is dependent on the maturity of the plant, when you buy it and how you treat the plant. With care, poinsettias should retain their beauty for weeks. Some varieties stay attractive for months.

• After you have made your selection make sure that the poinsettia is wrapped properly because exposure to low temperatures, even for a few minutes, can damage the bracts and leaves.

• After arriving inside, unwrap your poinsettia carefully and place in indirect light. Six hours of light daily is ideal. Keep the plant from touching cold windows.

• Keep poinsettias away from warm or cold drafts from radiators, air registers or open doors and windows.

• Ideally, poinsettias require daytime temperatures of 67 to 70 degrees F and night time temperatures of 60 to 62 degrees F. High temperatures will shorten the life of the plant. Move the plant to a cooler room at night, when possible.

• Check the soil daily. Do not allow the poinsettia to wilt. Water only when soil is dry. Punch holes in foil so water can drain into a saucer. Allow water to drain into the saucer and discard the excess water.

• Fertilize the poinsettia if you keep it past the holiday season. Apply a houseplant fertilizer once a month. Do not fertilize when the plant is in bloom.

Getting poinsettias to re-flower is not easy, and requires some patience and care.

In late winter to early spring (late March or early April), cut back each of the old flowering stems to 4 to 6 inches in height. Cutting back the stems will promote new growth.

In late spring to summer repot the plant into a larger pot, 2-3 inches larger than the previous. Use any well-drained soil, such as a blend of equal parts sphagnum peat moss, vermiculite and/or perlite. Thoroughly mix 1 tablespoon of treble superphosphate fertilizer (0-46-0) in each gallon of soil mix. Apply a slow release fertilizer to the soil surface. Make sure the soil is moist and place the plant in a sunny window. When all danger of frost has passed and minimum temperatures reach 55 degrees, the plant can be placed outdoors. Place the poinsettia in a shady location for two to three weeks to allow the plant to become acclimated to the new environment. Then sink the pot in a partly shaded area.

Turn the poinsettia pot regularly to prevent rooting through the bottom hole. A quarter turn each week will help to keep the plant growth even all around the pot. If the pot is not turned, one side the plant my get more sun than the other.

If a short plant with many flowers is preferred, pinch out the growing shoots to encourage branching. Pinching should produce more flowers and a nice bushy plant. The pinching should be done at 3 to 4 week intervals, according to the speed of growth. Pinch out the top ¼ inch by hand. Two or three large fully expanded leaves should be left below the pinch; this serves as a guide for knowing when the shoots are ready for pinching. Continue this practice until late-August, when the plant should have a satisfactory shape and number of shoots.

Keep the plant growing actively all summer by regularly watering and fertilizing every two to three weeks with a complete soluble fertilizer.

In fall, before night temperatures fall below 55-60 degrees F at night, (approximately September 1 in Colorado) bring the poinsettia indoors to a sunny location. Check the plant for pests and diseases and place the poinsettia in a south window.

Many pests can infest poinsettias. Wash off insects with mild soap and water, using a sponge or gentle spray. Mealybugs and whiteflies many require pesticide application or removal of infested plant parts. To remove mealy bugs, apply ordinary rubbing alcohol with a cotton swab.

Poinsettias are short-day photoperiodic plants, which means that flowers begin to form when the days are a certain length, or more accurately, when nights are long enough. Without long nights, this plant will continue to produce leaves and will grow but will never flower. You must make certain it receives no light from any source during the night.

Very short periods of light during the night may be enough to prevent or interfere with flowering. To get a poinsettia to re-flower you have to keep the plant in total darkness between 5 pm and 8 am starting around October 1st. Continue long night darkness until color shows on the bracts, The dark treatment should last until color shows in the bracts (approximately Thanksgiving). Even light from a street light can stop flowering. If the plant is grown in a room that is lighted nightly, cover the plant completely at dusk (5 p.m.) every day with a heavy paper bag, a piece of opaque black cloth or light–tight cover or place in a dark closet.

Flower initiation begins in late September and early October. Dark periods of at least 14 hours of uninterrupted darkness each night are necessary for flower set. Flowers mature from 60 to 85 days depending on cultivars, temperature and light intensity. Once you can see the flowers developing in the growing plants, continue the dark period until the bracts are almost fully expanded.

Temperatures should be no less than 55 degrees F at night, but not more than 70 degrees F during the day to give the poinsettia as much sunlight as possible. Night time temperatures above 70-75 degrees F can cause decay or prevent flowering.

Reduce the amount of fertilizer given after bringing the plant indoors. Growth is slower in the lower light intensity inside the house.

High night temperatures, low nutrition, dry soil or improper photoperiod may delay maturity.

Poinsettias are not poisonous, but like other non-food items, poinsettia plants are not edible and are not intended to be eaten. Keep plants out of reach of small children.

The authors have received training through Colorado State University Cooperative Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.

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This page updated:  November 1, 2006