Tropical gardens can vary from dry and desert-like, to coastal, to dense, lush and leafy environs resembling the dynamic workings of a rainforest. Many different garden effects are possible using tropical plants. You can also, on a small scale, transform a garden into a microclimate using tropical plants that are not normally found in your locality.
Types of climates
It is important to understand that there are variations in climate within tropical and subtropical regions, and that not all tropical plants like the same conditions. These are just some of the different climates which "tropical plants" come from.
Seasonal or Constant. Many tropical climates have two distinct seasons; a wet season (monsoons), with heavy rains and high humidity and a dry season, when there is little rain. Some parts of the tropics are much less seasonal, with temperature and rainfall conditions remaining similar all year round (eg. Honolulu and some other parts of Hawaii).
Mountain. Mountains can be high and cold in some parts of the tropics. There are even snow covered mountains in tropical New Guinea. Plants which grow on tropical mountains can be quite different to plants that grow in tropical lowlands.
Savannahs (Grasslands). Savannahs are tropical or subtropical open grasslands that are bordered either by rainforest or swamps or mixtures of both. They tend to suffer a greater variation in temperature than coastal or rainforest environments. They can be very humid and damp environments due to high moisture and open sunny conditions. Broad-leaved ground covers with bright flowers are very much at home in this environment.
Arid. Some areas that are tropical have large extremes when it comes to moisture availability. Arid zones are usually very dry, with poor soils such as claypans, sands or gravels, and are subject to occasional downpours that can result in flooding. Therefore, the plants that thrive in this type of environment are either very hardy or have very specialised survival strategies to meet such conditions. Arid environments can be much colder at night and hotter during the day than other parts of the tropics or subtropics.
Rainforest. The rainforest is one of the most dynamic environments that exists, with an abundance of species that often cannot be found elsewhere. Conditions throughout a rainforest are constantly changing as the forest undergoes a competitive aging process that sees many species unable to survive. Thus those that do remain do so as a result of highly specialised ecological refinements.
Coastal. Coastal regions can be a mixture of all those previously mentioned environments with the added complications of salt-laden spray, periods of heavy winds, nutrient poor soils, and at times encroaching sand dunes. Plants that grow in coastal areas need to be quite hardy to survive in such a climate. Being close to water has a buffering affect upon temperature extremes. They do not get as hot or as cold as otherwise similar environments that are further away from water.
WARM CLIMATES CAN CREATE BOTH GOOD & BAD CONDITIONS FOR GARDENERS
Plants tend to grow faster, longer, and more lush in a tropical climate.
Pests and diseases also tend to grow bigger and faster, but if plants are relatively healthy, they are able to recover faster from these problems in a warm climate.
Humidity can be higher and more prolonged than in cool climates.
Winds and storms can be more forceful.
Soil can dry out faster.
Foliage can suffer sun burn more readily.
What do these things mean?
Often, plants need to be grown differently in the tropics than they are in the subtropics or a temperate climate as an indoor plant.
Generally (not always), the same plant grows bigger in the tropics than in the subtropics, and bigger in the subtropics than in temperate climates.
Drainage is very important in tropical areas to avoid roots being flooded in heavy rainfalls.
Pants susceptible to damage from waterlogging might be better planted on mounds or slopes.
Plants need to be inspected for pests & diseases more often and action taken immediately. In a cool climate, you might wait for a few days or weeks to see whether insects develop into a serious problem, but in the tropics, they can develop from a minor to a serious problem over night.
(NOTE: These are generalisations only!)