Vanilla, besides being a fragrant extract essential to baking, is a vining orchid native to Mexico. It is not at all difficult to grow indoors given the proper conditions, but it may be difficult to induce it to produce the flowers, which are mostly lime green with long yellow tubes. The large ovate leaves are thick and waxy, and the vines can easily grow to over 100 feet long in the tropics, clinging to trees with aerial roots. The plants are self-fertile and in their native habitat, pollinated by indigenous bees. In cultivation, they are hand-pollinated to ensure production of the vanilla pods that carry vanilla "beans". This labor-intensive method is one reason that vanilla is so expensive. The Aztecs were the first to create the sublime blend of cacao and vanilla. Commerically, major producers of vanilla are Madagascar, Réunion Island and Indonesia.