The ornamental design for a skirting for a pottedplant container, as shown and described.
FIG. 1 is a front and top perspective view of skirting for a potted plant container embodying my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a right side elevational view thereof, the left side elevational view being a mirror image;
FIG. 5 is a bottom plan view thereof; and,
FIG. 6 is a rear elevational view thereof.
The broken line showing is included for the purpose of illustrating the environment and portions of the article, and forms no part of the claimed design.