Cheryl Isaak expounded:
I had a Miscanthus chinensis (variegated yellow and green) I tried to divide once - OMG, the thing had roots of iron! I couldn't get even one bit of it out of the ground! It was at the end of my driveway and grew way too big for the space over the years, it blocked the view. Most of it died about three to four years ago during a particularly harsh winter. I took advantage of the kill and got rid of the rest of it. I've got a lovely yellow baptisia there now, much more manageable!
I feel for your son if it's the same grass I had.....:o)