Growing unusual plants is a hobby for many gardeners during the cold winter months when they can't do much in their own yards. Exotic plants require specific growing conditions. The more the conditions are recreated, the healthier the plant will be. Research the plant you want to grow before making your final selection of exotic plants. There are thousands of choices for exotic plants.
Select the proper soil. Orchids, for example, will die in houseplant potting soil. They prefer a mixture that is high in bark and doesn't retain water. Cacti need a soil that drains quickly and has little organic material to decompose. Most cacti in the wild are in areas where there is little leaf fall to decompose and enrich the soil. Air plants, Bromeliad titllandsia, don't need any soil at all, naturally growing in crevices of trees and branches.
Adjust the temperature. Temperatures inside the house or on a patio may not be ideal for the exotic plant you select. Some like banana plants won't do well where temperatures drop below 67 degrees F at night and prefer temperatures in the mid 80s F during the day. Orchids developed in warm, humid climates, but vary as to the degree of difference between day and night temperatures and highs and lows they prefer.
Maintain proper moisture and humidity levels. Exotic plants that originated in the tropics need very high humidity levels, some as high as 80 percent. Place the plants on trays filled with pebbles and water to increase humidity. Or, put them in a terrarium or old aquarium. Clustering plants together in one place naturally increases the humidity. Misting the plants works for some plants but causes problems for others. Maintaining a high level of humidity is important when the plant is first purchased, as it most likely has spent its life in a greenhouse under ideal circumstances.
Fertilize the plant with the appropriate fertilizer. Camellias and gardenias need an acid-based fertilizer, for example. Exotic plants may go through a period of dormancy where there is no active growth; don't fertilize during that period.
Know the lighting requirements. Schlumbergera or Zygocactus are succulents that bloom once a year with vibrantly colored flowers. Poinsettia's leaves--bracts--turn to red, pink or white surrounding tiny white flowers. These types of plants will not bloom unless they have a minimum of 13 and 12 hours, respectively, of darkness. That means no light whatsoever. Opening the door to the room where they're housed may expose them to lighting in the hall.