Please, if it is possible: at the override vegetation of polygons will be
useful some option of grass. Kind regards.
In many cases, aprons may be substituted for polygons. Some apron materials do
not suppress default grass, but many do. Concrete seems to work best. You can
increase the transparency to zero, to hide the concrete texture, or you can
select a material that allows varying degrees of default grass to show
through, depending on the transparency and then add grass objects from the
library to create an aged look. This particular material is “taxi-shale.”