Feather dusters of nature

I have noticed more and more of these feathery plants in our area and I saw this one at the botanical gardens. Isn't it funny how something so simple in design can really catch your attention? I like the way they planted it in front of this little tree that seems to mimic its design and they both look like old fashioned feather dusters to me. The color is wonderful! The feathery purple tops look so soft, yet when you get closer, it definitely resembles coarse grass and I think it's a type of muhly grass, wild but people do plant these often to define edges of a garden area, or at least that's what I've observed around here.