The Institute for Nature Study (自然教育園) in Meguro is a park where you can find many different species of trees, plants and flowers. This institute is to preserve the natural environment of Tokyo’s marshlands, parks and forests and is mainly used for education and research. You wouldn’t think you’re still in Tokyo while strolling around the park. It has a unique and calming atmosphere that you’ll find more than welcome after being exposed to all the noises, crowds and lights of Tokyo. Close to Meguro station you can find many restaurants to eat afterwards.
Fee is 310 yen and except for Monday, it’s opened daily from 9:00 to 17:00 (no entry after 16:00 though). Located at ten minutes walk from Meguro Station (Yamanote Line, Toei Mita Subway Line and the Nanboku Subway Line). For a detailed map, check their official website.
Official website (in English): http://www.ins.kahaku.go.jp/english/index.html