Sorry Guest, you're going to have to repost your question - are you saying you've got Willow leaves on your Rhododendron, or woolly leaves? And a photograph would be good.

I wondered if they could be woolly yellow leaves. ?
There are so many possibilities here.

Hollow?

Not enough clues, Sherlock and Doc Watson, lol!

Wallow? Fallow? Pillow?

Strike the last one - that's daft! lol.

Wollow ,wollow, wollow the merry merry pipes of Pan.
Pigs wollow, oh no that's wallow.

LOL. Love it, Ob! ;-)

Ha ha, poor Guest though, must be getting really teed off with all these responses - but it is funny, sorry Guest.