I claim the ornamental design for a linkable planter container, as shown and described.
FIG. 1 is a perspective view of a linkable planter container, showing my new design;
FIG. 2 is an exploded perspective view thereof showing two end portions thereof as removed from a container portion thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is a right-side elevational view thereof, the left-side elevational view being a mirror image thereof.
The broken lines showing an additional linkable planter container and vegetation in FIG. 1 are included for the purpose of illustrating the invention in use, and form no part of the claimed design. The broken lines showing brackets in FIG. 5 are included to show environmental matter, and form no part of the claimed design.