>>>Say, do you think it would work to plant them in a container, maybe like a big barrel or bucket?<<<
It would work, but you need a pretty large bucket.
Remember that it has to be big enough so the flowers don’t overhang the sides. If they do, they will put their spikelets down on the outside of the bucket. (Maybe you could manually put them back in, but I never tried that)
I think I would sneak them in where there is a bit of a sandy spot with lots of sun, somewhere in the garden.
I forgot about the flowers. I have some sand that I can mix into a spot in the garden. I’ll have to get them in this weekend.