This morning I grafted a big-leaf hydrangea to a rose bush.  I am hoping to achieve a new variety which will have both the scent and full bloom. 
The national gardening association has been helping with tips since 1971!
That is an excellent pointer!  I am just starting with this, so I will look in that.  Are you familiar with different grafting methods?
Cleft grafting is a type that can be used for apple trees.
I need to practice that technique a bit more.  How about root grafting, do you know which flower types respond best to that method?