The Box elder tree, known for its hardiness, thrives best in well-drained, loamy soil rich in organic matter. Loamy soil is a balanced mix of sand, silt, and clay, which provides a fertile and well-structured environment for optimum root growth. This type of soil ensures adequate moisture retention while still allowing excess water to drain, preventing root rot. Aim for soil that is loose and crumbly, as this promotes better aeration and helps roots spread easily.