what is well drained soil
We live in the south of France and we have rich black topsoil with no stones in it. We wish to plant exotic plants; for example, a Yucca on a 30 degree slope. Do I need to add small stones or sand to the soil when I dig out the hole for planting the tree? Will that make it well drained?
Here is a link that will help you perform a soil percolation test.