Hickory is one of the most tension strong woods. It generally does not require a backing at all, since it is perfectly suited for a selfbow. A bamboo backing might even overpower the belly, resulting in set. Only if the grain is really poor, you need some sort of backing. Possibly bamboo, but there's plenty of other backings around. Rawhide, silk, linen or another slat of wood will all work. Bamboo can be difficult to source and difficult to work with for a beginner.
To answer your question, most bamboo species are strong enough for bow backings. Some are stronger than others (madake, tonkin), but all should be strong enough. Don't worry about the species too much; just select a high quality pole with no defects. Many bowyers use moso bamboo, because it grows in large diameters and is easily accessable. Many places sell high diameter bamboo poles. The world is a big place, so I don't know where to start giving you advice where to buy it.
