Hi I got 2 Arundina graminifolia - Hawaii bamboo orchid bulbs on ebay.
I planted long ago - no roots - no rot yet - one started a little growth on the stem - I attach a picture below.
wonder if i am doing right because I checked and i saw no roots. is the new growth going to be a new division and grow roots from above?
I mean should i bury it deeper so the new green growth is on the soil level?
I'm not sure what's wrong with your arundina. Better to uproot from the media and see what's going on under the soil.
My experience with Arundina is when new growth from one of the node is reaching about 6" tall. I cut the cane with the new growth in the middle and just cover it with soil. It will give out new keiki from the base and will grow happily.
My best guess for happy Arundina is just to let the new growth be a few inch tall then bury the cane deeper so that the base of the keiki is covered.