Swallowworts are highly invasive vines originally from Europe. Once introduced into an area, they quickly spread, climbing over native vegetation and completely taking over.
They are characterized by opposite or whorled egg-shaped leaves, vine-like growth, and milkweed-like seed pods, with tiny seeds attached to light fluffy parasols that readily ride the wind.
If you discover Swallowworts in an area and they are just getting established, get rid of them immediately. If you wait you will have a very real problem on your hands later. Simply pull them up. You will have to come back later to get the smaller ones, and the ones you missed. At the very least remove and destroy the seed pods before they ripen.
These are dangerously invasive plants. They grow fast, spread rapidly, and climb all over other vegetation, overwhelming other species.
There are native field plants under this mass of Pale Swallowwort!