In their native Mexico, poinsettias are a weed. They grow into tree-like plants that bloom annually. They are tough as nails, and can live for years with the right care. The No. 1 thing that kills them is kindness. Too much water and fertilizer is the worst thing for the plants, but don't let them completely dry out.
Poinsettias will be happiest next to a bright window, away from cold drafts but also not by a heating duct. If the pot is wrapped in foil, it won't need to be watered much, but remove the wrapping after about a month so that water can drain and salts and other impurities can be flushed from the soil. After that, lift the plant to feel how heavy it is: a light plant that has dried out will need water. Grow the poinsettia as a houseplant, the colors will eventually fade.
In our climate, the plants can go into the garden in late May, they can't tolerate any frost. They make a nice bedding plant growing right in the soil, and will triple their size during a summer outside.
When the weather starts to turn cold, bring the plants back inside. They will bloom on the windowsill, but not as nicely as greenhouse plants. October is when the light levels are perfect for blooming, 12 hours of daylight.
The plants can last forever, if the gardener wants to repot the poinsettia yearly.
They are poisonous, but don't worry, someone would have to eat lots of plants just to get a stomach ache. Plus, poinsettias are not tasty, so it won't be a problem.
Most poinsettias in this country are grown at Ecke Ranch, they tell the story of the Legend of the Poinsettia.
Happy holidays and enjoy your indoor plants.