Poinsettia plants (Euphorbia pulcherrima) remain one of the most popular holiday flowers. The familiar red blooms have been joined by even flashier colors. Actually, they are not flowers but modified leaves called bracts. The bright bracts are designed to attract insects to the tiny yellow flowers in their centers. Hybridizers have expanded the range of colors from the familiar red to pastel yellow and vibrant bicolors. Because poinsettias have been forced into bloom, they need some extra care to keep them in bloom throughout the holidays. While it may be easier to buy new plants each year, it is possible to get them to rebloom the next season.
January to march: keep watering a poinsettia whenever a surface is dry. April: starting april 1, gradually decrease water, allowing a soil to get dry between waterings. Be careful that a stem does not begin to shrivel. This is a sign a plant is too stressed and is dying.
As with most houseplants, they will benefit from an occasional feed during the growing season. An organic, balanced, liquid fertilizer once a month during spring and summer is recommended.
Loamy soil is ideal for most garden plants because it holds plenty of moisture but also drains well so that sufficient air can reach the roots.
Trim out dead and damaged leaves any time, pinching off or cutting off each of those leaves at its base. Avoid cutting into a plant's main stems or its crown, which is where its leaves and roots meet.
To keep the poinsettia in bloom as long as possible, maintain a temperature of 65 to 75 F during the day. Dropping the temperature to about 60 F at night will not hurt the plant. However, cold drafts, allowing the leaves to touch a cold window, or more importantly, lack of decent light, can injure the leaves and cause premature leaf drop
Increase pot size by 2.5-5 cm (1 to 2 inches) in diameter for plants that are growing in pots 25.4 cm (10 inches) in diameter or less. For larger plants, those growing in pots greater than 10 inches in diameter, increase the pot size by 5 or 7.62 cm (2 or 3 inches) in diameter.
For years, poinsettias have had the bad reputation of being poisonous. They certainly are not meant to be eaten by humans, pets, or livestock and ingesting poinsettias would probably cause some stomach upset, as would eating almost any houseplant. However, poinsettias have undergone extensive testing and there is no evidence that they are toxic or unsafe to have in the house. They are also safe to put into the compost.A more likely problem to watch out for is contact dermatitis. Euphorbias, the plant family that includes poinsettias, exude a milky sap when broken. Think of milkweed, another common Euphorbia. Many people are sensitive to this sap, which can cause an itchy rash. Be especially careful not to rub your eyes after touching the plants. To be safe, wash your hands after handling a poinsettia plant and try to avoid pinching or pruning them with your hands.