The ornamental design for a post-supported flower pot holder, as shown and described.
FIG. 1 is a pictorial view of a post-supported flower pot holder
constructed in accordance with my new design;
FIG. 2 is a planar side view thereof, with a view taken from an opposite
side and being a mirror image thereof;
FIG. 3 is a planar top view thereof;
FIG. 4 is a planar bottom view thereof;
The dotted line representations of a flower pot and a post as shown in
FIGS. 1, 2 and 3 are for illustrative purposes only and constitute no part
of my claimed invention.