The ornamental design for solar-powered hanging plant illuminator, as shown and described.
FIG. 1 is a side view of the invention in operation;
FIG. 2 is an enlarged side view of the invention;
FIG. 3 is bottom of the invention;
FIG. 4 is top of the invention; and,
FIG. 5 is a perspective view of the invention in operation.
The broken lines showing the plant, planter, solar panels, circular openings and light rays are for the purposes of illustrating environment and form no part of the claimed design.