Im still not totally convinced. But yes we both failed… the only variable we didnt try is chill hours. Perhaps your roots were so far down that they did not get enough chill? Perhaps your mulch is so deep from the 20 yrs that they never pop up?
This thread has me still wondering. To this guy they are invasive.
IF there is a next time… i think u or I should try getting some root cuttings in the fall and putting them in the fridge.
I know with your double rosette that tip rooting will result in the same disease… the only propagation technique that nobody tries is leaf bud cuttings… im not sure if the disease will pass via that route.
I just did a leaf bud cutting on a purple rasp and its taking so far. But i did it way too late…so its iffy. If i can get the timing right this would be the way to go for mass propagating… you have to do it on the primocane. I think.
