I finally got out to the area where I see both types of common milkweed, to get a photo of the red-stem version. Here in the Simcoe County area (central Ontario,Canada, about 55 miles north of Toronto) the milkweed has just started to bloom. I have always associated the arrival of Monarchs with the start of milkweed flowering. This year has held true, as I saw my first Monarch yesterday (June 26th) while shooting the milkweed. I went to a conservation area known as The Copeland Forest, about a 20 minute drive NE of Midhurst. There is a large meadow filled with lots of common milkweed, both green and red stemmed. I took a photo of both types and have created an album at http://photobucket.com/albums/a240/JohnBeaulieu/
so Monarch Watch members could see and possibly make comments on this red stem variety, which so far, I have never found Monarch caterpillars on. They always choose the green-stem variety. I will pay more attention this year, though.
I also saw my first wild, Swamp Milkweed at a pond on the same property. I'm sure I have seen it, but never knew what it was. Now that I am getting involved with Monarchs, I am looking closer and learning more. Photos of the swamp milkweed and that first monarch are also at the photo site. The monarch was feeding on both types of common milkweed.