Exotic trees, though they bring with them a brilliant and unique look, are not a very good addition to a native area. These trees are known for causing numerous problems due to their intolerance to South African soil, climate and rainfall. Read about the disadvantages of planting exotic trees below:
Exotic trees are known for their ability to become a nuisance due to their plague-like abilities. If these plants can grow and thrive in an area, there is a very high chance that they could outgrow the native plants and takeover the soil, causing any native plants or trees in the area to die. This can become problematic as this could create a huge fluctuation in the wildlife in the area that would have formerly been attracted to the native trees.
If these exotic trees do not thrive, they will die out. All this means is that you would have wasted your money on planting a beautiful tree that was not meant for the environment it was placed in. They could die due to the climate, the average rainfall of the area or the water content within the soil, though it could also be due to many other factors such as bugs.
Subsidence occurs when the soil beneath the ground shifts which can cause uneven surfaces that could pose a problem to structures within the area. This could be caused due to too much or too little water in the soil. An exotic tree may be used to a lot more, or a lot less water which means that planting an exotic tree can be problematic to the water content within the soil.