Thank for your answers but the flower is smaller than a hydrangea and more compact and it stays green?

If it is blooming this time of year, it is probably a species of Viburnum. Sometimes the flowers start out green and fade to white or pink with age.

Thank for your answers but the flower is smaller than a hydrangea and more compact and it stays green?
Sounds like my Snowball Viburnum, similar to Hydrangea but the leaves are more acid green.

http://images.google.co.uk/images?hl=en%26amp;...