Posted: 02/06/2012 at 13:54
Was the manure well-rotted? If not, it will damage the plant and needs removing.
If the manure was all that you gave it, it may have exhausted the nutrients in the pot. Scrape off the top two inches of compost, add some rose food (available from garden centres) and top with fresh compost.
Have you been watering it frequently? It will have dried out very quickly in the hot spell we've just had.
Finally, have you checked the compost for vine weevil? Look for white, C-shaped maggots with a dark head, about a cm long.