Along the pool fence I want to put a flowerbed. In the pictures you can see where I threw 3 blueberry bushes in. Well, now the grass is basically growing straight up and holding the plants in the hillside. A heavy wind will probably make them topple over. I am thinking about putting a flowerbed or retaining wall. It will be 2 foot away from the fence and about 2 foot out, probably 2 foot tall and might run it most of the way down the fence. See the picture of the wood style I want. Here my question... with such a small bed or retaining wall do I need to follow all the drainage rules of building a retaining wall?