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. Cynanchum laeve is considered a noxious weed in several states, and can be very difficult to eradicate from fields because of its deep, extensive root system. Like many other milkweed species, C. laeve contains toxic cardenolide alkaloids, and is a food plant for the caterpillars of Monarch butterflies.