Wrap the end of the barbed wire around the farthest cedar post once or twice to hold the wire in place.
Place a 1½-inch fence staple over the wire so the staple ends are against the cedar post. If you wrapped the wire twice, place the staple over the wrap that does not include the end of the wire. Turn the staple so that one side is slightly higher than the other.
Hammer the fence staple all the way into the cedar post. Tug gently on the barbed wire so it is secure; add a second staple along the same length of wire, if needed. Attach the remainder of the barbed wire to the rest of the cedar posts.