You mean the tall plants? Common milkweed, Asclepias syriaca.

Thank you -- googling the title, it definitely is a milkweed. Not sure if I'll keep it though, too many cons.

Lots of pros tho. Its native to much of the U.S. which means little to no maintenance, it has interesting flowers, it's a pollinator favorite (not just monarchs, but all of the insects like it), it's definitely a conversation plant, and it is the only way you'll have monarchs in your yard.

Plants of the Asclepias genus are the only ones monarch butterfly caterpillars can eat.