The ornamental design for a de-thatching, mulching and grass cutting lawn mower blade, showing our new design.
FIG. 1 is a top front perspective view of a de-thatching, mulching and grass cutting lawn mower blade showing our new design;
FIG. 2 is a side view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a front perspective view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a reduced bottom perspective view thereof shown in use condition;
FIG. 7 is a partial side perspective view shown in use condition taken along lines 7-7 in FIG. 6; and,
FIG. 8 is another partial side perspective view shown in use condition taken along lines 7-7 in FIG. 6.
The broken line showing of a lawnmower and grass in FIGS. 6, 7, and 8 is included for the purpose of illustrating environmental structure only and forms no part of the claimed design.