Okay.
Somebody from the Eastern side of the Atlantic help this poor dumb Yank out on this one.
"Shrubbery" as used by the Monty Python guys in "Monty Python and the Holy Grail" when the evil knight says, "We want a shrubbery!" Is this accepted usage or a joke? In the States we would never say "a shrubbery" to indicate a single plant. We would say "a shrub". A mass planting of shrubs would just be "shrubbery", or a specific mass planting would be "the shrubbery", but never "a shrubbery".
Cheers,
Bruce