It is self pollinating, its many seeds fly far and wide, they can produce twins when they sprout, the rhyzome (underground stem) remains when the vine is pulled, older rhyzome sections may break off and remain when it is dug out.
To control its spread, it is most important to destroy its pods (not compost: they will mature off of the plant). The plant can be dealt with another time.
Monarchs recognize that it is in the milkweed family and will lay eggs on it, but it is fatal to the caterpillars. Notice the flawless leaves - nothing can eat it. The Latin name translates to dog strangling vine.
That was only the 2nd monarch I've seen this season. Their troubles are another rant for another day.
At the back of the Little Bluestem Meadow, a few spreading dogbane blossoms were remaining in the shadiest places.
Down in the Fern Glen, an American copper was trying to get warm in the weak sun.
Dun skippers, male and female both, were alternately feeding and sunning.