The ornamental design for a concreteplanterbox, as shown and described.
FIG. 1 is a perspective view of a concrete planter box showing the present invention;
FIG. 2 is a top view thereof;
FIG. 3 is a left side view thereof, the right side being identical thereto; and,
FIG. 4 is an end view thereof, the opposite end being identical thereto.
The broken lines show internal surfaces, portions of the sides and ends, and the bottom of the concrete planter box. None of the broken lines form any part of the claimed design.