Common Milkweed

Common milkweed (Asclepias syriaca) is the primary host plant for monarch butterflies, meaning females lay their eggs exclusively on its leaves. The caterpillars consume the toxic, milky sap, which makes them poisonous to predators.

Yes, the plant contains cardiac glycosides in its milky sap, making it highly toxic to dogs, cats, and horses if ingested. Symptoms of poisoning can include weakness, difficulty breathing, and potentially fatal kidney failure.

Common milkweed seeds require a period of cold stratification for about 30 days to break dormancy before planting. They should be sown in well-draining soil and exposed to full sunlight to thrive.

The large, distinct seed pods split open in the fall to release seeds attached to silky hairs. Historically, this buoyant silk was studied during World War II as a hypoallergenic filling for life jackets.