Poinsettias are a often a great Christmas decorating idea, but more so in the northern hemisphere than here. The pots of poinsettia we buy at Christmas are forced into flower at that time. The link between poinsettias and Christmas comes as poinsettias, which are native to Mexico, are naturally winter flowering so bloom at Christmas in the Northern Hemisphere. The fact their flowers are a Christmassy red and they can be grown as potted plants also helps. Poinsettias flower in response to changes in day length. As days shorten and nights get longer, poinsettias and many other autumn and winter-flowering plants are triggered to bloom. Nurseries use this feature to manipulate their flowering, producing poinsettias in bloom at virtually any time of the year. If you have a poinsettia, enjoy its blooms now then cut it back hard at the end of winter.