The American Orchid Society calls Phalaenopsis the most popular orchid in the country. They are also called Moth Orchids because of the flower's physical resemblance to a moth. Placed in the proper environment, they are fairly stress free growers. Most species thrive in typical warm day, cool night, household conditions, when situated near a sunny window and humidifier. Depending on the species, their colorful flowers remain in bloom up to two months, partly accounting for their popularity as house plants.