Ime no plant attracts adult monarchs as well as the water snowball plant, Gymnocoronis spilanthoides. When I was working in an aquatic nursery, they were a magnet for them. It's a highly preferred nectar source. In years where there were hardly any monarchs around, the few I did see were feeding on the nectar of these.
__________________
Be who you are and say what you think. Those who matter don't mind and those who mind don't matter.