We did that with our last Pampas and it hasn't regrown thank goodness. The main problem at the present is an ever increasing New Zealand Flax. I keep hacking the outside off to reduce the size, but am loath to cut the height as they tend took look dreadful if lopped heightwise.
My doorsteps full of daffies in pots are now finished, so I am about to replace them with polys or pansies. Few tulips struggling in the wind and some smaller, lower bulbs all out, but the daffs are almost done.