In our horticultural practices in planting in the ground, a slight "hill" is made then the vegetable seeds or young plant is planted, then soil is mounded on top. The soil, of course, will gradually settle, sinking the roots, plus rain will wash down some of the soil. So every few days, soil at the base will be "raked" up to the mound. (The same thing is done for newly planted young fruit trees like lemon, lime, mango, etc. for a few months.)
I know that the Filipino and Chinese also do this as I have personally seen them do so. I think this practice allows for development of more feeder roots as well as aeration of the soil, not to mention prevention of root rot. Also, I know that in the "states" pumpkins, watermelon, squash, and some others are planted on hills. And I think this is for the same reason mentioned above.
I don't do this for plants in my raised garden, nor for potted plants for obvious reasons. However, for mature adeniums, I understand the wisdom of growing in mounded soil in a pot. Besides being aesthetically pleasing, this function helps prevent root rot and provides aeration.
My 2 cents worth.
-Kadie
