Thanks to all who took the time to reply. I wasn't thinking of digging
anything up in the countryside. Before planting anything, I think I'll
need to wait until the ground is soft and wet so that I can dig out the
bramble roots. I will certainly look at all the options mentioned in
this thread. I might try to bring on some butterfly bush cuttings in
my flower bed for planitng out next year. I also had the idea of
gathering ash seeds and scattering them on the area. The other problem
I have is the appearance of japanese knotweed. I've been keeping it
down for the last 4 years with pulling and cutting.