R writes
Ragwort on the other hand is a controlled weed (Notifiable to the local
authority)

No it is not notifiable - you do not have to notify anyone if you have
it growing on your land.

Ragwort is a native UK plant which is a primary food plant for the
cinnabar moth, listed on the UK Biodiversity Action Plan as rapidly
declining.

It is covered (along with spear thistle, creeping thistle, broad leaved
dock and curled dock) by the Weeds Act 1959. You have a responsibility
to stop any of these five weeds spreading from your land on to
neighbouring land, and DEFRA can take action if you do not do so. It is
not a problem if it is growing on land which is not used for grazing or
close to grazing land.

--
Kay