Sometimes referred to as exotic plants, tropical plants are those that thrive in warm climates, such as USDA Plant Hardiness Map zones 10-11, which includes the Deep South and Hawaii. Temperatures in these regions rarely reach freezing. These areas are generally hot and possibly humid in the summers and, for much of the year, temperatures are above 60 degrees F. Cactus, palms and orchids are examples of some tropical plants. Tropicals are often grown in greenhouses or as houseplants in non-tropical regions.
Cactus (Cactaceae) is a large family of succulent plants, defined by the 1997 Sunset National Garden Book as plants that retain water for use during periods of drought. Cacti are generally leafless and have stems that may be in the shape of pads or cylinders and are used for water storage. Most cacti are native to the Americas and have pointy spines that protect the plant from losing its water to animals. Cacti, particularly the tropical kinds, have large, showy flowers.
One of the largest families in the plant kingdom, the orchid (Orchidaceae) has more than 17,000 species, most of which are considered exotic and grow best in tropical or sub-tropical regions. Orchids generally have showy, uniquely shaped blooms on graceful stems that rise from large leaves at the base of the plant. Orchids need only a limited amount of light and well-draining, moist rich soil.
The palm (Palmaceae) family also has many varieties, including cabbage, sago, fan or queen. These plants are ubiquitous in Florida, southern California, Hawaii, Arizona and other tropical destinations. While some varieties can withstand colder temperatures, palms are generally tropical plants that require full sun, well-draining soil and little water when mature. Rather than leaves, palms have fronds, often in the shape of fans or feathers. Some palms flower as well, and many produce pods of seeds during the winter.