overwintering tree rose
by joanne
(Baltimore, Maryland)
Doug says that the chances of it flowering depend on how cold it gets in your home area. If it gets cold enough (around -5F) then you might indeed see some damage to the top part of the rose above the graft. Too many variables to pic from here to say it will definitely die or not.
If it does die, you won't get blooms of any kind - you'll have a dead plant that will throw shoots from the live roots but nothing will grow from the top.
Pruning tree roses is the same as pruning hybrid tea roses (pretty much anyway). :-)
Good luck