Did you remove the seed pods? They could've reseeded from the empty lot behind your house, since the fluff attached to the seed allows the seed to travel ;)

If you plan to harvest the seed, remove the seed pods as soon as they split. If you don't want to harvest seed or allow reseeding, remove the pods before they develop.

I grow A. tuberosa, A. incarnata, A. curassavica; all are controllable, and only reseed if I don't get to the pod quick enough...

Hi Tracey,
Actually I was more concerned that it would spread uncontrollably by runners as it seems to be popping up further than where I originally planted it. This is making me anxious that I will have a difficult time containing the milkweed.

We have a volunteer apparently from blown seed.

We also planted A. tuberosa but it only lasted 2 years. Seemed healthy but disappeared and didn't seem nearly as vigorous as the common milkweed.

We do get them popping up where we don't want them but it seems more so in my wet area's of the yard. karen

Karen, thanks for the information. I planted one in a boggy spot in the yard and the new shoots there seem to be more vigorous than the others. Is it difficult to control?