I'm wondering the same. There are some roses I just cannot propogate by baggie method and I'm hoping this method will work for them. Do you knick the stem? I applied some organic compost around the layering site, don't know that it could hurt. When I do baggie method, some take 3 weeks, some take months. The 7 sisters did not seem to root for me via baggie however, I accidently left some outside over the winter and in the spring I found them well rooted in their bags having survived outside in the winter. I've done it that way 2 years in a row now.