As a gardener I feel there is nothing worse than using those hollow bricks and allowing grass to grow between. Looks OK to start but then come the time to trim or cut the grass - never seem to get it low enough. Then as they settle and with the vehicles weight mud and dirt comes up and covers the bricks and in wet weather becomes a horrible mess.
Why not put 2 rows of 18 inch paving slabs down (on a suitable base) and you will then still have a strip of greenery in between and easy to keep cut, cropped and maintained.