This is a massive gardens and would take a couple of days to really see everything and enjoy it. Most of it is free but there is a small charge for the orchid garden which is worth it. There are so many different, beautiful parts of this well maintained gardens that at times it feels as though you are in a national park. We went back a second day to the children's garden as it was closed on our first visit and we could have stayed there for a lot longer as there was plenty to do and the kids loved it. As well as the plants and the water there is lots of wildlife, as you can imagine, we saw several monitor lizards wandering around the paths and swimming as well as plenty of birds and butterflies, we even saw some turtles. I would recommend this as a great free day out, the only negative is that it got extremely hot in the middle of the day and there's not much shelter as you walk around so I would aim to go early in the day if you want to enjoy it