To provide a program which assists a user so that an arrangement of plants arranged by the user is more appropriate. A program for causing a computer to function as: a layout acquisition unit configured to acquire arrangement information of plants arranged on a landscape by a user; a vegetation information acquisition unit configured to acquire vegetation information relating to influences exerted by the respective plants on each other; and a validity evaluation unit configured to evaluate validity of an arrangement of the plants indicated by the arrangement information, based on the vegetation information.