By Maggiehughes
West Midlands,
United Kingdom 
my rhoderdendrom looks lovely but i have noticed that some of the flowers are going brown on the edge of the flowers
20 May, 2012
It could be a number of things and I would say they are all physiological e.g.
Wind burn
Frost burn
Dryness at roots
You don't mention how long they have been blooming so it might just be simply a case of 'ageing'
23 May, 2012