whats wrong with my viburnum?

I can see some flecks on the back of a leaf on the top left of the picture - are they scale insect, or an insect of some kind?
Checked the other picture you posted, its a bit out of focus, but does look like some kind of woolly deposit. Trouble is, there's no obvious contender to cause both these problems. Might be Viburnum scale, might not be, could be some kind of fungal infection, but less likely. Even if it is scale, it can't be treated easily, and no point at this time of year unless you can actually see the little scales.

I would say it's old age and autumn tint.

You need to look at the other pic, DocBob, showing the stems all covered in white fluff

Thanks for directing me Bamboo, I hadn't seen the original question and photo. This is wooly aphids. Paint it with methylated spirits.