Been here in various seasons and always something to see. Less crowded than other locations for cherry blossoms and autumn leaves, can be a mosquito farm in midsummer. Located on the site of the Shogun's medicinal plant garden, it has an interesting history with some of the first specimens of certain plants to come to Japan. I actually like how it is kind of wild and non-touristy (with very few amenities) but have a few quibbles. Most things are labeled with scientific names so you can find on your phone, but more common names in other languages would be helpful. The geology, history, and architecture here are also very interesting but there's almost no explanation of it. The medicinal garden is tiny and I think more people would be interested in a larger and more detailed reconstruction of the Tokugawa-period garden. In all, if you're a plant nerd like me you'll be happy. Outside April and late November, not sure how much attraction it has for casual tourists at present.