The ornamental design for a wreathbase, as shown and described.
FIG. 1 is a front perspective view of a wreath base showing my new design;
FIG. 2 is a back perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a back view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof;
FIG. 8 is a bottom view thereof; and,
FIG. 9 is an enlarged portion view labeled, “FIG. 9,” in FIG. 1.
The dashed-dot lines in FIGS. 1 and 9 illustrate the boundary lines of the enlarged portion view of FIG. 9 and form no part of the claimed design. The even dashed broken lines in FIGS. 2 and 4 form no part of the claimed design.