You haven't said where you are in the UK in your profile, unfortunately, but if you're in the south, could it be drought because you've not been watering?

Hi i am in the north east of england, and we have had an exceptional hot dry spell, and i have made sure this plant has been well watered throughout this period, because at first i myself thought that was the problem.
Ive only just joined this site about 30 mins ago, so still finding my way around,

I think that you've had plenty of rain in the last week or so, haven't you, so if the problem was drought, then it should resolve itself. Sometimes people think they've watered well and sufficiently, but haven't, so I'd ask quite how you watered, what with (spray gun on hosepipe?) and how often?

Hi

during the hot weather even when there was a short shower, i still watered all my garden with a hose pipe. because this bush was looking particularly sad, it got more than other plants and it was watered every day. I can say with 90% certainty that it isnt lack of water that it is suffering from.

If it was drought, then the whole plant would be affected eventually surely?

If it was drought i would have thought that the top of the bush would show signs first as the lower branches took up what available water there was.

The branches that are affected are affected from top to bottom, and there are branches that are perfectly healthy from top to bottom also.

It is not just one section of the bush either, these dried out branches are interspersed with healthy ones.

Not sure if you realise the pic i have showing is of the affected plant

there's no picture with the question, and if you mean your avatar pic, its too small to see any detail, sorry. I'd be inclined to cut out the shrivelled branches at the base now if they're not carrying flowers - Philadelphus should be pruned in this way every year after flowering anyway, having about a third of its stems reduced to the ground, and the others shortened a bit.
I have a blog on watering, you can read it by clicking on my avatar, selecting blogs on my profile page and selecting Watering for Beginners. Watering is an art, and is much better done infrequently and well rather than daily in smaller amounts, but have a read if you feel like it, it's not very long. I'm not saying that was definitely the problem, and if you could add a photo to this question rather than as your avatar, that might be useful.

Well i think i hve managed to put a picture with this question, but there are two pictures on my profile which i thought was where pictures went. Ill find my way round this site if it kills me.

Thanks for your advice Bamboo and being patient

Checked the pics - odd, the leaves in some parts look stunted and are curled at the edges. Nothing springs to mind as a cause, but is it growing in open ground, not contained in any way, and with no barrier underground, such as concrete, lots of rocks, at some point? It doesn't look like drought either.

Its been in open ground for the past 6 years in the same spot and although my dog continually damaged it during the first 3 years there, and it rarely had the chance to flourish, or grow very bushy the last three yrs have seen it come on in amazingly - until this year. Im not aware of anything present undertheground, but of course i only dug deep enough to plant the bush, and havent excavated deeper