This article reviews the silviculture of walnut in Britain and conside
rs the case for planting common walnut (Juglans regia) or black walnut
(Juglans nigra), neither of which is native to Britain. In addition t
he results of four provenance experiments planted in southern Britain
in 1986-87 are described. The results of the experiments., confirm tha
t walnut is extremely sensitive to site conditions and should only be
planted on the most suitable frost free, fertile, well drained and dee
ply rootable sites. Species comparisons show that J. nigra is more tol
erant of poor sites than J. regia, but at the only suitable site for p
lanting walnut there was little difference between the two species. Ve
rmont, Ohio and Illinois provenances of J. nigra all performed well on
the best site in the Chilterns and relatively well on the other poore
r sites.