Thank you to everyone for your suggestions.

1. Making an object a grass eco-system really doesn't cut it because it is populated with grass objects that are so irregular in character that they extend too far beyond the perimeters...unless someone is selling a grass pack I don't know of that is more like a single small cluster?

2. Frank T: I'm not sure what you mean by making a black and white distribution map, but I am guessing that I would end up with the same problem using grass object modules to populate it.

3. I checked out Solosplace and saw an couple of examples that do what I'm thinking, although I have to note that I've yet to see anyone do something on the order of a large city park with carefully cropped lawns and lots of defined edges....and Pete hasn't gotten back with me yet....

4. Sangelico: that looks good and would work, it doesn't have to be absolutely perfect straight edge, just one that doesn't extend a foot into the sidewalk! LOL If I could airbrush that on as individual objects onto the object as an ecosystem, that would seem to be the way to do it...do you have the address for Wallis' Grass Pack 2? I couldn't find it.