Something that's loamy is full of rich soil. There are some plants that thrive only in loamy spots.
Loamy soil is composed of loam, a very rich mixture of clay, sand, and silt. If a patch of earth is loamy, it's full of nutrients and well drained — perfect for growing most plants and trees. The Old English root of loam is lam, "mud" or "muddy earth," which stems from a root that translates to "slimy."