I don't live in Hawaii but am going there on vacation tomorrow. I thought I might check out this forum and saw your question. I would guess that the "stem" part should stick out of the dirt. I hope to bring some bamboo orchid bulbs home also.

I bought from a plant catalog. It came with instructions but I don't remember what they said but I do remember planting them in peat moss very shallowly with the stem sticking out. I kept them moist and warm and they never sprouted, just rotted.

you may have kept them too wet. They grow wild around here and we are not in a "jungle" area. The stem should be sticking out of the dirt. They are cute !