What type of backfill material is recommended for plants that require good drainage?

The recommended backfill material for plants that require good drainage is sandy soil. Sandy soil consists of larger particles, which creates more space between them, allowing water to flow through easily. This results in excellent drainage, preventing water from pooling around the roots of the plants, which can lead to root rot and other moisture-related issues.

In contrast, clay soils have very small particles that are tightly packed, which can lead to poor drainage because water does not move through them easily. Loam, while a balanced mixture of sand, silt, and clay, provides good drainage but may not be as efficient as sandy soil for plants that specifically thrive in well-drained conditions. Silt can also retain moisture more than other types of soil, making it less suitable for drainage-sensitive plants.

Therefore, sandy soil is the most suited for backfilling around plants that need good drainage.