rescuing an overgrown border

I've got a decent sized old flower border that has been overrun by the dreaded ground elder, I've got the horror everywhere but I thought I would try to clear this area as it's surrounded by elder free grass and drives.

It consists of an elm hedge around 6ft tall and then some huge tree stumps from the bastard service trees that we felled last year (they were overhanging the house and yes that's their name not just swearing) It's been abandoned for at least 5 years, and up untill last year was in deep shade, however there's still a few plants in there I would like to keep.

Snowdrops (I've heard now it the right time to move them)

Winter aconite

Tons of bluebells, really tons.

Two different orange lillies

one red peony

one single stem of a blue iris (if I can find it again)

comfry

My plan was to dig up some of each of the plants above, or all of them if I can find enough pots, keep them in pots for the year and either cover the ground in black plastic or roundup it, probably a combination, as getting plastic round the stumps, hedge and the mock orange that I want to keep as well will be hard. do any of those plants I mentioned need anything special doing to them to survive such treatment? The borders around 16m long by 3m wide by the way and with the treeroots in there I don't think I can try to dig it and sieve it.