The Garden Maze is a beginner track in BTD5 slightly modified from the Protect Monkey Town map, just with the monkey village removed and only one bloon spawning point. The bloons start from the top and exit at the bottom of the track.
"Don't like the fact that you can't play the track the Protect Monkey Town mission is on? The problem is solved! A fun and easy new track where bloons spawn from the top and make their way through the garden maze before they reach the exit at the bottom!"