When I first set up this air layering experiment, basically ring-barking the chosen stem of the rose, I was unsure how on earth the stem was going to stay alive without its 'Cambium' growth layer. I'd always though that all the action, particularly water transport, took part there. Shows what I knew! Not only is the stem alive and healthy but flourishing with new growth like mad.It seems the inner structure of the stem is quite capable of carrying water and nutrients on its own. I assume this is only the case with the young, green, canes and will not start carelessly ring-barking roses with the whipper snipper when clearing weeds.