I have some 12-ft. tall prairie grass in my suburban yard's bed that is spreading outward and has a vacant center of about 2 ft in diameter. I know I need to divide it, but what is the best way. Also, it is very hard to cut down in the spring. Should I burn it? Do I need to get permission from the city to do that? Please advise.

Judi, The vacant center is natural as the grass clump grows. Grasses tolerate burning well but be sure to check with local ordinances about burning. Most do not allow it. However the grasses can be cut down with pruners or electric hedge shears. First tie the grass clump with twine to make clean up easier. Warm season grasses are best divided in late April or May as they start to wake up. For dividing get out an axe (I'm not kidding here) or a really sharp spade. Prairie grasses form a thick sod. Just cut off some of the outside sections and replant. You won't need big sections. The inner area can be left to rot or can be dug out. Happy digging!