I’m probably not the right person to write this article. I’ve killed or driven every poinsettia I’ve had to suicide. I’m hoping this year will be different. So I rolled up my sleeves and hit the search engines.
Here’s what I’ve learned. In their native habit ( Central America ) poinsettias grow to ten feet tall. The colored parts we consider to be the flower are actually bracts, colored leaves surrounding the smaller less note worthy flower. Contrary to common belief they are not poisonous, but the milky sap may irritate some people’s skin.
Water the poinsettia freely when the top of the soil feels dry. In the winter that usually means a good soaking twice a week. But your house may be different. Put it in the sink and soak the soil, letting the water freely flow out from the bottom. If you live up north keep the leaves from touching the window. Also keep it away from drafty doors. Poinsettias do not need much sun, they’ll be more than happy a few feet back from a bright window if that’s the only way you can keep them warm. They will love a bright sunny window, if it is also warm there.
They love humidity. If you can’t put them in a humid bathroom or kitchen, keep some water in the saucer. I know you are not supposed to keep plants sitting in water, but a few really need that humidity and damp soil. Poinsettia is one of them. Keep the water fresh. It is the bacteria in the water and damp soil, not the dampness that hurts the plants.
To reflower your pointsettia keep it in complete darkness ( a closet ) for 15 hours a day from Oct first until Thanksgiving. Put it in a sunny window during the day. A dark paper bag will also work to keep it dark. Once Thanksgiving arrives put it back into a sunny window and you should have flowers by Christmas.
Leaf drop beginning at the bottom and working up on a poinsettia can be from root rot, too little water, too much water, or too little light.
They can get botrytis fungus, the red leaves get brown areas at edges which grow bigger. You may see a powdery substance on the plant. Keep water off the leaves and plant and it should do just fine.
Poinsettias drop their leaves when the air or soil is too dry.