University of Illinois Extension
Just the facts: The length of time your poinsettia will give you pleasure in your home is dependent on (1) the maturity of the plant, (2) when you buy it, and (3) how you treat the plant. With care, poinsettias should retain their beauty for weeks and some varieties will stay attractive for months.
After you have made your poinsettia selection, make sure it is wrapped properly because exposure to low temperatures even for a few minutes can damage the bracts and leaves.
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 60 to 70°F and night time temperatures around 55°F. High temperatures will shorten the plant’s life. Move the plant to a cooler room at night, if possible.
Check the soil daily. Be sure to punch holes in foil so water can drain into a saucer. Water when soil is dry. Allow water to drain into the saucer and discard excess water. Wilted plants will tend to drop bracts sooner.
Fertilize the poinsettia if you keep it past the holiday season. Apply a houseplant fertilizer once a month. Do not fertilize when it is in bloom.
Forcing a poinsettia. To get a poinsettia to reflower you have to keep it in total darkness between 5 pm and 8 am. Start this around October 1st and continue until color shows on the bracts; usually around early to mid-December. Any little exposure to light can prevent flowering. Covering the plant with a light-proof bag and placing it in a closet might work. Night time temperatures above 70-75°F can decay or prevent flowering.
Poinsettia Facts Poinsettias are native to Mexico. The Aztecs called the poinsettia Cuetlaxochitl. They made a reddish purple dye from the bracts.
Chile and Peru called the poinsettia the “Crown of the Andes.”
Poinsettias are part of the Euphorbiaceae family. Many plants in this family ooze a milky sap. Some people may have skin irritation from the milky sap.
In nature, poinsettias are perennial flowering shrubs that can grow to ten feet tall. The showy colored parts of poinsettias that most people think are the flowers are actually colored bracts (modified leaves).
Poinsettias are priced according to the number of blooms. The more blooms, the more expensive the plant.
The flowers or cyathia of the poinsettia are in the center of the colorful bracts.
Poinsettias have been called the lobster flower and flame leaf flower.
Poinsettias are not poisonous. A study at Ohio State University showed that a 50 pound child who ate 500 bracts might have a slight tummy ache. Poinsettia sap that can irritate the skin and cause an upset stomach if consumed in large enough quantities.
A fresh poinsettia is one on which little or no yellow pollen is showing on the flower clusters in the center of the bracts. Plants that have shed their pollen will soon drop their colorful bracts.
Poinsettias were introduced into the United States in 1825 by Joel Poinsett.