Rhiannon Macfie Miller wrote:

It was a dark and stormy night, and as the people of uk.rec.gardening
huddled around the fire, Martin Brown told them this story:

Most things that can grow and ignore it are shrubs, but ISTR one of the marigold
family produces its own herbicide and is supposed to be able to take the stuff on
and win. I've not tried it myself.

According to
http://www.e-garden.co.uk/index.asp?...&categoryID=70
Mexican marigold keeps it at bay. Though it also says that
it's ugly and smells awful, so I might just stick with the
ground elder.

(My trouble is that it comes in from next door (the single
one of our six immediate neighbours who does nothing with
their garden) and so I can never get rid of it completely.)

It is fairly shallow rooted so you can put 12" slates into the soil down the boundary
line and pretty much prevent further ingress. I have never really had much bother with
it. Just spot weed new leaves as they appear and never let it set seed. You need
patience to exhaust the extensive stored energy in the roots. That is why a combination
of chemical attack and digging out works so well. YMMV

Regards,
Martin Brown