Black-Eyed Susans are native plants, so they work well in most North American soils, as long as the soil is well-draining. Black-Eyed Susans tolerate a wide range of soil types, including clay soil and lightweight loam. However, they perform at their best in neutral pH soil with good moisture content that is neither dried out nor soggy. If your soil dries out constantly, or contains lots of sand, consider mixing some compost into the soil to improve moisture and nutrient content.