This is a derivative of 'Rose' by Bratskbars. The original STL file consisted of 13 intersecting meshes which made it non-sliceable. 3DCoat was used to convert the meshes to voxels and fill the hole in the back. The complete object was then exported to a good quality printable STL.

Blender was used to split the meshes into the flower and leaves groups. Then 3DCoat was used to import the flower and leaves meshes, voxelizing them, filling the hole in the back and using a boolean operation to cut off the part of the leaves that intersects the flower. Then the flower and leaves objects were exported to two perfectly sliceable STL files. The flower and the leaves should fit together perfectly and are glued together.

The use of 3DCoat was explained on the 3D Printing Today podcast (Link) episode 107 and further. Highly recommended!