In message , Martin
writes

It's against the law not to destroy Giant Hogweed, if you find it on your
property.
How can anybody retail it legally?

It is not exactly against the law not to destroy GH - Under section 14
of the Wildlife and Countryside Act 1981, it can be an offence to plant
or grow specified plants in the wild, including Giant Hogweed and
Japanese Knotweed. Problems involving these plants can be referred to
the local authority for the area where these weeds are growing as some
local authorities have by-laws controlling these plants. There is no
statutory requirement for landowners to remove these plants from their
property.

This information from NERC may be of interest http://tinyurl.com/29qhf7
--
Robert