@sunsetsail, the type of Poinsettias I have are the Hardy Poinsettias, which are orange in color, and are drought tolerant for the wicked hot sun we have and the drought periods.
I have had the traditional red Poinsettias for gifts at Christmas, and I did put them into my garden one year. That was after the last frost of winter, and they survived for months and started turning red. I don't remember what happened, but they died.
The Hardy Poinsettias are fantastic. They bloom profusely and every seed that drops makes a new plant. The young rabbits love to eat them, and I let them all grow so the rabbits will avoid my other plants in the garden. I love orange in the garden as well, so they are a win-win for me.
I am sure that a hard frost will damage the leaves of your plants, but I'm not sure if it will kill the roots. Hope this info helps.
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