Are they planted where they are getting enough sun? Are they getting fertilizer from your lawn? If so, too much nitrogen may be to blame.
Thank you for the suggestions but this doesn't answer my question because they are potted in big planters and in full sun.
I still have not found out why my pampas grass will not plume.
Are you positive of your identification?
yes, I have 2 white in plume when bought and 1 pink bought from nursery online in root.
hmm..so you saw them plume once. How big are the planters? What type soil are they in? Do they have good drainage? How often do you water them?