PROBLEM TO BE SOLVED: To provide a vegetation basic substance, by which a three-dimensional tree-planting on the slope surface can be carried out, so that a latticed expanded body is made unnoticed, and plant growing on the slope surface is also easily achieved. SOLUTION: The vegetation basic substance comprises a vegetation bag 12 at least containing tree seeds 13, and a rectangle sheet 9 formed consecutively with the vegetation bag 12 and having an upper side longer than a consecutively formed part 9a. COPYRIGHT: (C)2003,JPO