In article , Sacha
writes

I've often thought that if I dug up some Couch Grass and labelled it
with it's proper name Elymus repens I'd probably sell some.

I don't think there can be any doubt!

Well, look at the range of other invasive weeds you can buy at any
garden centre!
Meanwhile the government's only just prohibited the sale of three really
disastrous foreign aquatic weeds which are blocking whole rivers and
filling good-sized lakes.
--
Sue ]