Can I divide pampas grass that I just bought right out of the pot?
Yep, I’ve done that exact thing before and have also done it with daylilies and what I call “monkey grass” which is otherwise known as lirope. I took the plants out of the container, shook some of the potting soil off of the roots and then hacked at them with a huge butcher knife. I felt awful doing it, because it just doesn’t seem right, but it worked beautifully! I also do that with the impatiens that I plant in containers. When I get them in the six-pack at the nursery, I take one out and just pinch off half of the root system and sometimes divide the plants if there are more than one in the section. Good luck!