Posted: 13/01/2015 at 18:47
We have a ponticum growing up between two others - i had to tie ribbons round the purple flowered branches to tell the difference. Once i had done that the differences in the barks became quite obvious - in our case the ponticum is quite scaly, whereas the others have a well defined pattern almost like a snakeskin. Not sure all the non-ponticums look like this, but worth having a compare.
Also Peanuts, if I remember rightly you are in Camberley? If so, there is a specialist rhodie grower (gets gold medals at chelsea and everything) in Churt (down south of Farnham) called Millais. They are really friendly and really knowledgeable, and I bet if you brought them a sprig of one in flower they would be able to identify it for you. Just check the website before you make the journey - they have quite random opening times