I have located milkweed in my area, southeast Id./northern Ut., that resemble antelope horn milkweeds, but have beautiful purple flowers and a darker green leave around them. They do not grow in swampy areas, but in dry sidehills or disturbed areas. Are they another variety of the antelope horn? I gathered a few seeds from the plants when the kids opened. Will they die if they are stored at room temperature, and do they need cold stratification.
Certified GKH Gardening Expert
They are likely a different species of Milkweed.
Here is a link that may help you with identification.