Just a warning and a sad tale of woe from me, I'm afraid. I planted one last year in my neutral soil, tried to care for it, but although it flowered, it just gave up on me and died. As they're very expensive, I'm not trying again! The Nursery had no explanation except that it might have been vine weevils - it wasn't. No sign of any at all.

Good luck with yours - why not ask the supplier?

My rhodo book suggests it may reach six feet in height and spread in 10 to 15 years. It does not mention any extra feeding being required.
The author of the book runs an excellent rhodo nursery in Scotland (website is www.glendoick.com) - you could try e-mailing them for advice

Thank you both for the replys, My garden slopes down a fair bit im going to try this at the top end (high and dry) wish me luck.

I will update.

A photo from May 1 year on.

http://www.growsonyou.com/photo/slideshow/222877-rhododendron-graffito/all