Sapwood, even one year seasoned sapwood, tends to check badly once the bark is removed. To avoid this, coat with shellac immediately after removing bark.
Another issue is that it tends to degrade much more quickly than heartwood. So storage after cutting should be indoors.
Assuming you have done these things, it can certainly work in a bow, as many have shown. That said, a sapwood limb bow can be tricky and I would not have liked to have tackled one as my first osage bow. As you have already seen, pins and small branches are prevalent and must be worked carefully. Be sure to take your time and ask advice here. Do you have any pics of the stave?
