My city has many government-funded Institutes, and we can visit some of them during the summer. But this botanical garden is open to the public all through the year as long as people pay about 3 us dollars per person. I said before that my city has lots of parks, but if I truly want to be surrounded by nature and relax, this is the place to go to.
This garden is visited not only by those who's interested in plants, but by the elderly, school children who want to learn something about mother nature. In fact there are many explanatory boards before each plant, and people can learn not only about Japanese plants but also foreign kinds that are preserved in the greenhouses so that they can survive in Japan.
The best season to visit this garden is the spring, but as the temperature is mild also in the fall in Japan, I could see many people. I have to say my pictures often don't include many people, but I've tried to avoid taking pics of people because of their privacy. And this place was indeed having more people than usual presumably from other prefectures.