I would also leave it be. Green canes are a good sign. If the ends of the green canes are brown or black, cut it back to the green part and seal the ends of large canes. I use Elmer's glue to seal any cut canes as wide or wider than my pinky.
I wouldn't use any chemical fertilizer, but you could top dress the plant with coffee grounds, crushed egg shells, banana peels or compost.
My roses are just starting to set leaves. A couple that looked dead (brown canes) are setting leaves. I don't give up until the canes are black and the roots sparse and brittle. Even then, I sometimes cut them at the ground level and pray for resurrection (kidding, but roses sometimes come back from apparent death).
