Gardening Questions Companion planting

Hi Andrea - I;m doing a 'Prairie' style bed this year - I'm using Stipa tenuissima as the grass base (currently growing from seed) and planting lots of Echinaceas through it. Also got a single yellow Rudbeckia in there, a daylilly and a few other bits and bobs. Not done this sort of thing before, tho, so don't know if it will work out as expected! I've not taken any pictures of it all yet, but will do so eventually...

Does it get sun? How about Verbena Bonariensis or V.rigida? They are prairie-type plants too, to add to Sid's list. Annual Rudbeckias or Gazanias would look bright and cheerful, or if you want a fluffy look, what about Nigella? You can get pink, white and shade of blue now AND they seed themselves! If you don't like the prairie or fluffy looks, how about Penstemons - they would look lovely in that bed.

Me - I have a bed waiting with this and Stipa gigantea and I plan to put my dark-leaved Dahlias in there. Is that madness? I'm hoping the fact that the Dahlias are greedy plants and so will take all the water will also suit the Stipas. I just think the contrast between the two could be pretty exciting.
Last year, we had them amongst Echinacea, Verbena bonariensis, Eryngium, Fennel and Poppies - somniferum and orientale - and that all seemed to work quite well.

Thanks there are lots of suugestions there for me to try!
Would love to see pictures of yours Sid when you have some.