This is a complex question. Poinsettas need to be subjected to daylight control. It is not an easy job for amateurs without the proper conditions.
Not all poinsettas are supposed to have red leaves.
Mexico
poinsetta
poinsetta
poinsetta, rose
Mexico
No they can not change colors
deep vibrint red
mortal flower
The Phosphorus change colors is Chameleons.
No, they are two separate plants.
sometiime somewhere
Bradenton and Sarasota Florida