There are a few reasons for having a Garden wall. One reason is to mark your territory, normally this is done by using the guide of what we call here in Thailand, the ‘Shanote posts’. These are small round white concrete markers that are put in the ground by the local government office, to let people know where there land starts, and where their neighbours land finishes.
Another reason for a wall is to keep out or even in, animals, chickens, pigs, dogs, cows, and so on.
Another type of wall is what we call a retaining wall, this is designed to support and retain the built up area of land (soil). This wall has to be a much stronger design, sometimes requiring a drainage system also.