"G. Able" wrote in message
...
It was a 4 foot shrub growing between some gorse bushes. Had just a very
few stems, covered in quite big spherical pale yellow flowers (but not
very
substantial looking, like e.g. mimosa).

Was driving down the Oxford ring road at the time, so details might be
dodgy


Any ideas?

Kerria japonica fits the description, most often seen as the double form,
but the pale yellow single escapes into the countryside from time to time.

--
Charlie, gardening in Cornwall.
http://www.roselandhouse.co.uk
Holders of National Plant Collection of Clematis viticella (cvs)