Propegating a climbing rose

I've had several failures and a few successes trying to propagate an old rose from my Mothers garden. I used most of the same steps others have, however I put it in a mixture of pearlite and peat. Used Rootone, and then put a plastic bag (I used a gallon one) over the entire rose,and secured it with a rubber band around the pot taking care not to touch the top of the cutting, (making a mini-greenhouse). I keep mine in a bright shady location. It takes about 5 to 6 weeks before you might see roots coming out the bottom of a 4" pot. I try to get a cutting that has bloomed and cut the blossom off also. As I say, I've been successful only about 1/3 of the time.