All honey — clover included — is made by honeybees. Bees feed on the nectar and pollen of various plants, then turn their collections into honey through a series of secretions. The honey takes on the flavor of whatever flowers the bees feed on, so if they primarily visit clover plants, they produce clover-flavored honey.
Clover is a creeping plant in the pea family which produces large amounts of nectar. In many regions of the world, people use clover to control erosion on banks and hillsides, as it roots well, holding back the soil. This plant is also used for animal fodder. It can grow in most terrains, is not expensive to maintain, and naturally attracts honeybees.