Very small museum, takes less than an hour to visit. There are some everyday utensils, living quarters and you can see how the typical northern Thai house looks like.
Lovely walk with plenty of benches to rest. The greenhouses are super fun. I did not get to walk the whole garden but the green houses had most of the flowers that were spread amongst the place anyways. Also very instagrammable!
Be sure to do the Tree Canopy Walkway (also referred to as 'The Boomslang') while at Kirstenbosch Botanical Gardens. http://www.sanbi.org/gardens/kirstenbosch/tree-canopy-walkway
Very quiet place outside of city center. There are mostly trees, I wouldn't call it a garden, but it's a natural pretty place pleasant to visit nonetheless.