Growing the tropical milkweed (as an annual) has been great, even though I have several other native species in my garden. Not being programed to die off in the fall, the tropical milkweed keeps on growing and flowering long after the native species have started to die back for the season. I have a photo from my monarch/milkweed album http://photobucket.com/albums/a240/JohnBeaulieu
that shows a pot of tropical milkweed (the all yellow form) still blooming after after we have had a couple frosts here in central Ontario.
Most garden plants have died back, the leaves have all turned colour and are half down. This pot was planted later in the spring and has not formed any pods yet. Most of the pollinating insects are now finished... I had better get busy with a small artists brush and do some pollinating, as I want seeds of this all yellow variety for next year. I may bring the plant inside and see if it will survive (in a south window) and produce pods. If not, I may cut it back and hope that it resprouts. That would make it easier to maintain over the winter and then I could put it outside next spring.