looks like 'bridal wreath' to me and I'd prune immediatly after flowering but see what others think

That's when I prune mine, too - after flowering.

Gosh, Pam and Ojibway, that was quick! Thank you. Yes, it is Bridal Wreath. Last year I must have waited too long and cut it back in the autumn, because this year there were virtually no flowers. Very sad!

I prune mine after flowering too Gattina.

Everyone's right - this is one you do immediately the flowers fade - the next year's flowers will appear on wood grown the previous year.

Can I extend this question and ask how hard one can prune it back? does it have to go to the ground? I would like to get the optimum shape year after year, but I don't want it to get too large, nor do I want all the flowers to be at the end of the branches.

No, not to the ground - usual procedure is to prune back what's flowered and reshape the whole bush, reducing what you need to reduce. The idea is it will put on more growth which will flower the following year.

I only prune mine after flowering to keep its shape - but mine is large Gattina. I am not sure you will be happy with the results if you try to keep it small?

Denise, I should be very happy to see it grow enormous, but it would outgrow it's space and probably overshadow some other, smaller favourites and see them off in no time. I have been trying to take cuttings so I can have others round the rest of the garden where they'll have more space to spread, but I am not sure if they are still alive - spring will tell!

If you remove all the flowering shoots, you will be left with a very small shrub - as people have stated above. You could try pruning just a third of the 'old' wood out, down to its base, and keeping the flowering shoots to the space you want, cutting back to a new shoot. It might work?!

Gattina, I didn't answer your query about taking it to the ground - no is the answer - if you do, you will lose flowers for at least one year, probably 2, maybe 3.

Although it's a long, fiddly job, you can follow each shoot back as the flowers fade and cut them back to where new growth is just starting

Mine is quite old now and I do what Andrewr has said above, it keeps the plant in shape and I always have a lovely show of flowers. My bush grows at the bottom of a steep slope where I try to keep the height in control.

Do you refer to it as 'Sideshow Bob?' That's how it immediately looked to me! Sorry - my warped sense of humour!

arching branches of white flowers is what mine does and thats what I grow it for, its about 4' tall and nearly as wide, beautiful in the spring with a deep rose Ribes at its side