Larson and research technician Ingram McCall then keep track of when the leaves, called bracts, on each of the 800 poinsettias turn color. More than 100 poinsettia growers from North Carolina and beyond attend the open house every year. Larson notes that poinsettias are the nation's most popular potted plant, even though they're only sold one season each year. This is a pressure-packed crop. You have to time it perfectly.
Poinsettias are actually small trees that belong to the Euphorbia plant family.
They are native to tropical regions of southern Mexico, where they bloom naturally in December and have been placed in churches at Christmas for centuries. Joel Poinsett, the first U.S. ambassador to the newly independent Mexico, introduced the plant to the United States in the 1820s. When Larson started working with poinsettias in the 1950s, only four varieties were popular. The two red varieties accounted for more than 90 percent of the poinsettias sold. One pink and one white variation divided the rest of the sales.