Cynanchum laeve

Cynanchum laeve is a vining perennial herb native to eastern and central U.S. states and Ontario. Common names include sand vine, honeyvine, honeyvine milkweed, bluevine milkweed, climbing milkweed, and smooth swallow-wort. The root system of C. laeve can cause it to be very difficult to eradicate, especially in agricultural fields. It is a larval food of monarch butterflies and milkweed tussock moth larvae. C. laeve can cause eye irritation if touched and can be toxic to humans and livestock if consumed in large quantities....read more on Wikipedia.