Wanneroo Botanical Gardens has it's own 36 hole mini golf course amongst the beautiful gardens. The course is spread over most of the garden, so even if it's busy you won't see many other people.
Thursday's and Sunday's are Night Golf night (if you choose to go to this, take mosquito repellant!).
At the end of your game you can relax at Leapfrogs Restaurant or visit the ice creamery. The gardens are filled with walkways to wander too.