Trouble with detail meshes

I am having trouble using the detail meshes of the terrain editor. I made a plant mesh, added the materials to the leaves and saved it as a prefab. When I place it in the scene it works fine but after painting it on the terrain with the terrain tool it only has one huge leaf and nothing else.

I have also tried making the plant a merged mesh but the painted vegetation is just like the one on the right in the image.