The ornamental design for a combination vertical plantholder and growing stand, as shown and described.
FIG. 1 is an isometric view showing my new design;
FIG. 2 is a second isometric view;
FIG. 3 is a front view;
FIG. 4 is a rear view;
FIG. 5 is a side view, as seen from the left side of FIG. 3;
FIG. 6 is a side view, as seen from the right side of FIG. 3; and,
FIG. 7 is a top plan view of the combination vertical plant holder and growing stand of FIG. 1.
The dot-dash broken lines depict boundaries to the claim and form no part thereof. The evenly spaced broken lines depict portions of the combination vertical plant holder and growing stand that form no part of the claimed design.