We know of only three remaining populations in Missouri. All persist on small remnant tallgrass prairies in north Missouri. As best we can determine, there are fewer than 100 plants at these three sites. We have a good indication of their range because records confirm this species grew as far north as the Iowa border and as far south as the Springfield area. Within this range they probably were scattered and sometimes locally abundant.
Threats are minimal to two of the remaining populations because they are managed on public land.
The third, on private property, has a reasonable level of security through cooperative management with the landowner. Rangewide, this species is threatened by habitat loss, overgrazing, poorly timed hay mowing, wetland draining and improper use of pesticides. Pollination by large sphinx moths is an essential part of their life history, but it is uncertain whether there are enough plants at any of these sites to attract pollinators. There are few remaining plants in Missouri. Restoration of sufficient habitat and the knowledge and public support to reintroduce this species back to these habitats seems unlikely.