The main factor that prevents the growth of tropical plants in the northern part of the United States is the climate. The tropical plants require specific conditions to grow and flourish, including warm climate throughout the year, higher precipitation, lots of sunlight. This conditions are lacking in the northern part of the United States where we have smaller amount of sunlight, mostly cloudy sky, and the winters are extremely cold and with lots of snow, and this will contribute to the dying of a tropical plant.