Red poinsettias are the traditional Christmas flower in the United States and throughout much of theworld. Poinsettias (poin-set-ie-uhs) provide a cheerful Christmas spirit. White, pink and marbled colored plants are also available.
The showy, colored parts of the plant, commonly called flowers, are actually modified leaves or bracts. The inconspicuous true flowers are located in the center of each whorl of bracts. They are green, have no petals and bloom with yellow flower parts and pollen.
Selecting Your Poinsettia
Choose plants that have clean, healthy, dark green leaves and colorful bracts. Be sure to check the underside of the leaves for insects. Avoid plants with missing leaves or bruised, broken or spray-damaged leaves. Plants shedding yellow pollen are over-mature. Healthy plants last longer and are worth the extra price.
On a cold day (below 40°) wrap the plant and pot in paper for the trip home and purchase at the end of the shopping trip. Even a slight chill or draft can cause the leaves to drop later on. Unwrap the plant as soon as you get home and place it in bright light away from cold or hot air drafts. Pierce the foil at the bottom of the pot for drainage. Water with lukewarm water if the soil is dry.
Place your poinsettia in a sunny window or the brightest area of the room but don’t let it touch cold window panes. The day temperature should be 65°-75° and 60°-65° at night. Do not place on top of a TV set because it gets too warm while it is operating. Temperatures above 75° shorten bloom life and below 60° cause root rot. Move plants away from windows at night or draw drapes between them.
Examine the potting soil daily. Never let the plant wilt or it will lose its leaves. When the soil becomes dry to the touch, water the plant with lukewarm water until some water runs out of the drainage hole, then discard the drainage water. Poinsettias do not like "wet feet." Repotting is not necessary during the winter.
Spring & Summer Care
As days lengthen and light intensity increases in March, side shoots often develop below the bracts. The old leaves and stems can be removed above this new growth. If all the old leaves have fallen and bracts have faded, the old stems may be cut back to six inches above the soil.
The plants may also be repotted at this time with a commercial potting soil or a mixture of 1 part soil, 1 part sphagnum peat and 1 part sand. If the plants were grown single stem (non-branched with several plants per pot), it is best to discard them. Reduce watering frequency in proportion to the amount of foliage removed from the plant.
Poinsettias can be grown indoors as foliage plants in summer or moved outside whichever is most convenient.
When frost danger ends in May poinsettias may be grown outdoors. Choose a wind protected, sunny location with some protection from midday and afternoon sun. Sink the pot to the rim in a well-drained soil. Rotate the pot every two weeks to break off the roots growing out of the drainage hole. Fertilize monthly according to directions with a houseplant fertilizer. Check water needs frequently because the soil can dry out quickly in summer.
Between May 15 and August 1, cut off the tips of the plants occasionally to get a shorter, bushier plant with more branches.
Fall Care & Re-blooming
Bring the plant indoors September 1 and place near the sunniest window. Beginning October 1, the plant must receive 14 consecutive hours of uninterrupted darkness each night but it must also get bright light during the day. Poinsettias bloom naturally by Christmas if exposed to the normal period of darkness and daylight after October 1 provided the dark period is not interrupted by turning on the room lights at night. Street lights shining through room windows may also delay bloom. The night temperature during the dark period must be between 60°-65° while flower buds are being formed, or bud set may be delayed or terminated.
Plants must receive bright sunlight during the day for good color to develop. An artificial light source is often required to supplement low fall and winter sunlight. Fertilize every other week and keep the soil from becoming too dry. Plants need extra nourishment while being forced into bloom.
After the bracts show full color, usually by Thanksgiving, the dark treatment is no longer necessary. The key ingredient to producing a quality plant is good light during day and 14 hours of total darkness during bud set.