Houston, we have a problem!!
The common milkweed (asclepias 'syriaca') is a major disaster.
First off, now that they are blooming on their 5-6' stalks, the only 'pollinator' they attract are Japanese beetles. The plants are heavy with them.
Second off, the stalks are prone to being blown down by wind or pushed down by heavy rainfall.
And third (and this is something everyone considering planting them should be WARNED OF) is that they are pervasive. Last year I had 2 seedlings with no where to put them so temporarily healed them in the stump bed and the crab bed. When they came up this Spring I dug them up and put them in the ring bed.
In a couple of weeks, I dug them up again (from the stump & crab bed) and composted them. And again. And again. It seemed that no matter how deeply I dug, how carefully I sifted the soil, new sprouts come up from roots that travel down to China.
Now when I see sprouts, I paint them with full-strength Kilz-all herbicide. I WILL get them out of the stump/crab beds.
As for my previous post where I mentioned I would be removing them from the ring bed, I'm now forewarned. I will not try to dig them up lest I sever/stimulate the roots. I will cut them down instead and begin a regiment of Kilz-all directly to each stalk. It may take some time to do the job, but they will be removed! For the moment, however, I've cut off all their tops/flowers to thwart the beetles.
Don't you just HATE it when something you dreamed of turns out to be a garden nightmare?
As for the asclepias incarnata & asclepias 'ice ballet' - they seem well behaved, beautiful, attracting bees by the bushel and smell like heaven. They can stay. But I'll keep an eye on them too.