If I was to plant a wildflower meadow, be it seed or with plugs.

Would I be able to take divisions or dig up bulbs or corms etc of some of
the plants, or would it be against the law. Or would it be still regarded as
a cultivated meadow.

I seem to remember being told that if a garden plant escaped into the wild,
and it continued growing for 10 years. It was then deemed to be a wild
plant. Would my meadow be the same but sort of in reverse, ie would my
meadow then be regarded as wild after 10 years.