Billy Rees mows his newly greened up lawn along Wesleyan Drive Thursday--inspired less he said by cherry blossoms en route to full bloom than by "an invasion of some new kind of grass.'' Rees said he looked forward to a more important invasion during the Cherry Blossom Festival, though: visits from some of his 12 great grandchildren. "The highlight is just driving around and seeing the sights,'' he said. "We just enjoy being together. It's a family reunion.''