Wish I could help! Can you advise where you are geographically (Uk, elsewhere)? as that may help narrow it down a bit. Also, if you can get a nice close up zoom on the leaves and flowers that may help other garden 'experts' a little...
I don't recognise it from what I can see - it looks vaguely like a plant my MIL has in her garden, but it's much bigger with different coloured flowers. And I don't know what that is called either.
Ahh well, mad pink fountain plant will have to remain a mystery.
I really like it, looks totally bonkers when in flower, all hot pink with the stems fighting to get on top. And more importantly it is very unfussy, even I managed to grow it from a tiny clump of dried out roots.
It flowers late summer into autumn and is beautiful. We live on the south coast and it is totally hardy here, but seems hardy further up country. As I said before try looking on this website for more info www.headgardenerplants.co.uk/plant.asp?val=LESTHU the website will list your local stockist if you want to buy one. Good luck!