I don't think any stave, hickory, osage, yew, mulberry, etc, that is good enough for a self bow should be used for a backed bow. Backing isn't necessary for good stave to make a good shooting bow. As I said, I see backing as a way to make bad bow wood good bow wood.
In my area, osage would be a better option because of the humidity and even osage is effected by it. Hickory is very hygroscopic, meaning it readily takes on moisture from the atmosphere and hickory in slow to release that moisture back into the atmosphere.
I have made some very good bows from hickory. It is one of my favorite bow woods but during the humid summers and until the dryer winters it can loose 10 or more pounds of draw weight and become very sluggish because of the humidity.
A personal example...I made a sinew backed hickory. Both the wood and the sinew/hide glue are effected by humidity. When I made the bow it was 56#@26". Within a month it was 45#@26". I sent it to a friend in Colorado and within a month it was 65#@26". all because of the relative humidity of the areas. Pat