I cut mine back in late winter, every year. It's stumpy and looks kinda bad for a while, but eventually fills out with lots of new growth. I only had 4 plumes on my plant the first time it bloomed, but this year was amazing. I just don't like the way this particular grass looks when it matures, if it isn't kept trimmed....all of the old dead brown bits give it a ratty appearance. So my personal preference is to chop it down every year.

Pampas grass is almost indestructable in our zone. I couldn't advise you as to how much to trim yours back in zone 6. I cut mine back to approx. 8-10 inches from the ground in late February, early March. It's full again by June.

I suppose whether or not you cut it back, depends on how much room you are willing to give it to spread out. And it WILL spread out. If it isn't cut back, it eventually becomes a monster of a thing, which will require a chain saw or machete for "trimming" at that point. I'm not kidding. Just ask anyone who has experienced hacking through the jungles of mature clumps of Pampas grass...they'll have horror stories for ya, and likely the scars to prove it, as well. Those razor-sharp leaf-blades can do serious damage to any exposed skin. And once a clump gets that large, it's nearly impossible to get rid of, should you decide you don't like it. My brother had to burn his Pampas grass to get rid of it.....fire got out of hand and the fire department had to be called to come put it out!!! It's funny now, but wasn't at the time. His overgrown Pampas grass almost burned down the neighborhood.

Renee

Thanks Renee. My Pampas grass has grown VERY!! tall. It doesn't seem to have migrated much yet but sounds like I will have to be more persistent in controlling it. What a funny story about your brothers experience. I will definitely not try to burn it. I admit I have been wondering what to use to cut it back. It is so tough and sharp!! I have already found out my hedge clippers will not do the job and I have no experience with chain saws (scary things).
Thank you again for the info.

No, hedge clippers won't be of much use. I don't care for chain saws, either.....as you said, they're a bit scary. I use loppers....the kind you would use to prune small tree branches. But first I trim away most of the sharp blades of grass with large grass shears, so I can get in with the loppers to cut back the old canes (bloom stalks). I wear gloves and clothing that covers my arms and legs.

Good Luck -- stay safe!
Renee

Good advice.