"Bigus" wrote

Are nurseries generally cheaper than garden centres, or does it really
depend on the individual place? Does anyone know any cheap places for
bedding plants around the Oxford area? We want some black grass, maybe
other
grasses, and butterfly/bee attractive plants such as lavender.

In my experience they usually are, but the real killer is that they usually
are much better quality plants because they grew them from
seed/cuttings/plugs and know how to look after them and most probably have
decades of experience.
With most plant families it's also better to visit a specialist nursery
where the choice will be significantly greater as GCs only stock plants they
can sell in bulk. It's often the only place to buy that unusual plant.
Just don't expect a tea room & toilets although there are some notable
exceptions. :-)

--
Regards
Bob Hobden
W.of London. UK