They are partially felted, but with some judicious yanking the yarn mostly unravels. So, the ceremonial robe is growing as those poor old hats are being cannibalized. You can see a heathery-turquoise cable knit thing at the top of the picture, which is re-forming on the needle.
Plus, after a week indoors, the beargrass is getting brittle. I tried soaking hanks of it and they soften right up, so yay, the robe continues to get its share of plant matter.