a blue rhododendron

The closest you'll get is a lilac or purple, there's no true blue one - just like roses, there's no real true blue one of those either. There is a genetic reason for this - breeders have been trying to crack this one for years!

As said, the nearest to a blue is one of the ones called Blue Diamond.
We have a very dwarf one which is nearly blue, but for the life of me I cannot remember its name, nor can I find a label.

Did you find a blue rhodo? We sell plenty of blue varieties, unfortunately we can't sell our plants outside of NZ, but thought you might like to look at our website to see the selection of blue flowers that are available. I have Azurwolke in flower at the moment and believe me, you don't get any more blue than this - it is true blue blue!!

Just googled it and found a couple of pics - one shows dark blue blooms, the other paler blue with pink, oddly, can't tell if the colour fades or changes or starts out different, or if the pink is a different plant behind. Looks like they're available in Holland or Germany, but not in Britain. Thanks for the info though, Rhododirect, at least I know now that we've finally got a proper blue rhododendron!