The ornamental design for a planthanger, as shown and described.
FIG. 1 is a top perspective view of a plant hanger according to the present design, the plant pot shown in dashed lines is for illustration purposes only and forms no part of the present invention;
FIG. 2 is a bottom perspective view of the plant hanger according to the present design, the plant pot shown in dashed lines is for illustration purposes only and forms no part of the present invention;
FIG. 3 is a side elevational view of the plant hanger according to the present design;
FIG. 4 is a top plan view of the plant hanger according to the present design;
FIG. 5 is a bottom plan view of the plant hanger according to the present design; and,
FIG. 6 is a bottom exploded perspective view of the plant hanger according to the present design.