Like DQ said, your betta won't eat the bamboo.....but bamboo isn't an aquatic plant and can't be fully submerged, it'll just rot and foul your water. But so long as the top portion with the leaves are exposed, it should be fine.....though I find that most tanks are too deep to leave the leaves exposed.
Weekend feeders are a BIG no no. They will only foul the tank water, and theres a good chance your betta won't even touch it.....and if they DO eat some of it then they'll stuff themselves silly and end up with SBD.
Bettas can go many weeks with out eating, unless your going to be gone for 2+ weeks they'll be fine without food.