I am of the school that if a piece of land is left to nature , nature will take its course and what will grow on its soil will. So if the orchids grow nearby and fancy your field then in time they will find it and flourish. They may have been trying for a while but not had the opportunity to show themselves by being trampled .
I moved into this place as a croft on a hill , when I fenced off the house from the animals , an old garden grew back which is now the outline of my new garden.