I've been told that poinsettias are not red but white; and to make them red, you must do something or something is done to them before they go to the stores. Exactly what is done to make them turn red (including the history of that)? Can you help?
Certified GKH Gardening Expert
The poinsettia "flower" is actually not a flower, but the leaves of the plant changing color. They can be either white for red naturally. Here are directions for making them run color: https://www.gardeningknowhow.com/ornamental/flowers/poinsettia/how-to-make-poinsettia-turn-red-make-a-poinsettia-rebloom.htm