Can anyone tell me what species of milkweed this is? https://www.flickr.com/photos/82741306@N03/albums/72157710746332957 It appeared in my old field this year, the first time I've ever seen it. Sadly, I didn't think to get pictures when it was in bloom; if I recall correctly the flowers were mostly white with some lavender-ish hues in the center of the Asclepias -looking inflorescences. Also, it bloomed after the Common Milkweed had already gone to seed.
It has opposite leaves and branches coming off a single main stalk about 1.5 meters tall. A look at internet sources led me to consider "Aquatic Milkweed," Asclepias perennis , though most pages say this species doesn't occur in MI (though maps show it in Indiana). Also, A. perennis is supposed to only grow in soil that's continually moist, which isn't true of my old field, though there are marshes to the north and east of the field. I live in a rural area about half way between Kalamazoo & Battle Creek.
Has been a banner year for Monarchs here this year (at least one larva is visible in one of the pics in the album). Hope this is an appropriate place to post this.