I have moved one. Roots as large as my forearm.
Dont sweat it. The plant broke into pieces and I just winged it and planted half the thing. It is huge now and I will have to dig it again due to invasive tendencies the branches are shading astilbes.
Its 3 years since it was transplanted. Pieces of roots left at the old site are making new plants.
I had no idea the plant was so stridant.
I might have to take the whole thing and put it on the back hill.