One of my favourites. Had mine 10 years now she's done really well, although last two winters(not this 1) The sub zero temperatures have not helped.I do very little in the way of maintenance because im growing her through a trellis. A general fertiliser once a year(slow release granules around the base) and thats about it. As you say you have only had it a couple of years,the last 2 to 3 years winter frosts and snow have not helped. This plant needs a good 5 years to really get a hold. Hang in ther Rosy and i feel sure it will come through. (Let it Be is a favourite expression of mine) As they say let nature take it's course, All good things to those who wait Etc. Good luck