Here is Asclepias syriaca with an eastern tiger swallowtail feeding on it we saw in early July at the Ontario Botanic Gardens. This was a dry area but we saw quite a bit of it growing in the wild in the damp areas.
Nice photos Rick and Tony :) At my last apt in Toronto, I had one small flower bed in front of my front window, maybe 4x6 or 8 feet; I grew a few things in there, nothing easily stolen or expensive, since it was right on the sidewalk, right downtown, and vulnerable to humans and their danged pets (why do so many dog owners think the world is their toilet?). but there was a pre-existing yucca that flowered spectacularly, and a probably self sown patch of milkweed- it was spreading, but wasn't yet a problem..
west central alberta, canada; just under 1000m; record temps:min -45C/-49F;max 34C/93F; http://picasaweb.google.ca/cactuscactus http://urbanehillbillycanada.blogspot.com/
Asclepias variegata seems to be scarcely in cultivation. Anyone growing this. Seneca Hills did offer, but mine died.Charles Swanson z6A MA NE USA
NE Massachusetts (New England) USA zone 6 (5B to 6B)
gardens visited, photographs: www.flickr.com/photos/wildmeadow