Your store-bought potted poinsettia just begs to be planted, and they can be grown as landscape plants in Florida. However, they struggle or fail in areas subject to regular frost and need regular protection. Florida is home to native poinsettias too, so lets compare them.
The popular store plant, is Euphorbia pulcherrima, a native to Mexico & Central America. It is named after Joel Poinsett, an ambassador to Mexico who brought it back to America in 1825, but has a history all the way back to use by the Aztecs. More on its history can be found here. While not considered an edible plant, it is a myth that this poinsettia is poisonous. Plants with milky sap can be irritants and some people can be very sensitive to it, so it is still advisable to keep it out of the reach of children and pets. Read about this and holiday plants that can harm pets, at this link. The colorful part of the poinsettia is not a true flower. The flowers are the small yellow parts at the center, surrounded by colored leaves called bracts.
To use tropical poinsettias in your landscape, plant in good sun but limited exposure to artificial lighting. If you plant in spring, give it a couple of weeks outside in the shade, so that it has time to adapt to the stronger light. They do best in moist, but well-drained & fertile soils. After the last frost, prune it to remove the faded red bracts, or back to live wood if it was killed back by frost. Keep pinching it back during the summer to encourage a bushy plant & flower head production. To color up, tropical poinsettias require a month or two with 14 hours of darkness daily. Strong street or home lighting may prevent or retard the plant’s ability to change color. A poinsettia under a sheet may look good for Halloween, but unless you want one for Thanksgiving, plant it where artificial light won’t cause a problem. When grown in mild conditions, they can stay red into spring. Fertilize them once a month March-October.
Florida has two native poinsettias, the wide-ranging, red tinged E. cyathophora , commonly known as Painted Leaf and the endangered E. pinetorum, found only in the lower part of South Florida. They are smaller, wild relatives with a similar but more modest look than the ornamental tropical poinsettia. We’ll focus on Painted Leaf, which is grown throughout Florida and the United States. A self seeding annual or short-lived perennial, its appearance is more spreading, and may blanket an area. Stems grow up to 3 feet high and the leaves are variable from plant to plant, differing from very narrow to wide. They do fine in moist conditions, however they are sand loving and content in drier soils. Fertilizing is unnecessary. The pollen is foraged by insects, including bees and butterflies. It is a host plant to Sphinx moths and their caterpillars. “Bloom” time is throughout the year, mostly early spring-late fall. So, you are less likely to see its colors at Christmas, but it will perform the rest of the year and need no special protection during the winter. The toxicity is not as well-studied as the cultivated tropical poinsettia, and the same general caution should be used.