I used to work near Ezuko (Lake Ezu) and noticed many banana trees whose bananas never seemed to ripen. Curious, I asked an older employee why they never ripened, and he said it was because the soil was poor - but that answer didn’t satisfy me, so I researched it and found that they are fiber bananas, raised not for their fruit but for their stalks, which could be harvested yearly and turned into cloth. (This is called “seni banana” - 繊維バナナ - and clothing made from the fiber can still be found online.) The Hosokawa lords, who had a summer house nearby (still marked by a plaque), raised them mostly as a vanity project. Kasegawa (加瀬川), which originates from the springs at Suizenji Park, flows under Densha Dori and is added to by the springs behind the library, which is chock full of banana trees and deliciously cool natural water, as can be seen by the photos at the link. Parking is plentiful here and there, and the walk from the tram stop not too far. Small pools originating from springs abound, and Kasegawa itself is clean enough to drink this far up from Ezuko. There is also a large boulder (pictured) which is popular among the youngsters to jump from into the stream. If you have children, it is an accessible location to cool off on a day off. There is no shopping in the area, so bring a picnic. Much info at the link. - William
https://www.furumono.jp/kumamoto-outdoor-about-ezu-park-basyou