I have this growing "wild" in my yard in a certain spot. Didn't know what it was for 5 years. It's tenacious and almost impossible to kill... trust me, I've tried. I'd love to have butterflies but the only thing that it seems to attract is.. well, NOTHING. I've pulled it up, cut it with a shovel, don't water it, nothing! Survives the coldest winters w/no protection (at least -20*F), grows to be about 5' tall, extremely xeric, poor poor poor soil (mostly rock & sand).
Anyone want any seeds? I've got probably.. 15? seed pods that are still green (they won't 'ripen' for about another month or so.. usually in August).
And I've never seen monarchs in my neighborhood, so I know I won't be denying them a place for munchies. Only butterflies we have are the white cabbage butterflies & swallowtails.