Tysmmm!!!!!!<333 I was also thinking of adding a bamboo forest area in the corner of the island for shiho like i did before i flattened my island
ohh okay! i believe bamboo trees can also be stunted using a fruit tree sapling and they can also be cut through their growth cycle so you might want to experiment with different sizes, the bamboo shoots, the bamboo material and cut down bamboo for variation. you could also place a bamboo wand as a tiny bamboo!
here are some items that may fit that theme:
torii, azuma gazebo, hearth, zen stone, outdoor bath, pine tree, pine bonsai tree, stone lion dog, blossom viewing lantern, cherry blossom pond stone, pond stone, tall lantern, mossy garden rock, steamer basket set, pagoda, kerokerokeroppi bridge, deer scare, tea table, imperial partition, shoji divider, Osechi, warrior statue, raccoon figure, stacked senmaizuke barrels, zen low table, zen bench, kerokerokeroppi lantern (if you don't like having keroppi's face, you can always turn it around), kadomatsu, blossom lanter, mini dharma, senmaizuke barrel which i see you're already using

, kerokerokeroppi tray, mochi pestle, go board, zodiac figurines, paper tiger, wooden fish, kerokerokeroppi doll, festival zongzi, traditional tea set, incense burner, low screen, bean tossing kit, paper lantern, floor seat, moss ball, yunomi teacup, zen cushion, round pillow
here are some of the bamboo related items:
bamboo shoot lamp, bamboo wand, bamboo noodle slide, bamboo doll, bamboo shelf, bamboo partition, deer scare, bamboo bench, bamboo floor lamp, bamboo speaker, bamboo basket, bamboo candleholder, bamboo stool, bamboo grass, bamboo drum, bamboo lunch box, bamboo sphere, bamboo stopblock, bamboo hat, bamboo wall decoration, bamboo lattice fence, green bamboo fence, bamboo slats fence
i think a zen rock garden or temple might be good additions to the bamboo forest!