What is milkweed? Milkweed are herbaceous perennials, about 3 feet tall. The flower cluster forms a globe atop the plant's rigid stem in the summer. The flowers come in various colors, and are fragrant. Leaves are broad-oblong and light green. Seed pods resemble small cucumbers. The pods in turn burst open in late summer to early fall, exposing their seeds. The seeds are attached to white silky hairs which are carried with the slightest wind.

Its presence is dwindling, along with the monarchs.Nearly 60 percent of native milkweeds have vanished in the last 20 years. Since then, monarch butterfly numbers have dropped 80 percent. This loss happens to coincide with the wholesale use of the weed killer Roundup on corn and soybeans which have been genetically altered to tolerate the herbicide, starting around 2003. Habitat loss, real estate development, climate change, and parasites also factor into the decline.

It is the stuff of life for monarch butterflies. Monarchs are specialist feeders, meaning they will only eat a specific kind of plant (milkweeds), and cannot survive without it. Monarchs lay their eggs on milkweed, and milkweed leaves serve as the sole food of monarch caterpillars.

It's both medicine and poison.Milkweed was named after the milky sap which contains latex. Its scientific name Asclepias is the name of the Greek god of medicine. Monarch larvae retain the toxins they consume in milkweed leaves and as butterflies remain toxic to predators. The toxins that protect the monarch can harm humans. Make sure the sap doesn't get into your eyes and if it does, seek medical attention as it can cause significant damage.

Milkweed plants are easy to grow.Asclepias spreads both via seeds and underground stem structures called rhizomes, forming colonies. Collect seeds after the pods have ripened, but before they have split open. The seeds are wind-dispersed, so be careful when gathering to place in a paper bag to avoid losing them. Seeds can be directly sewn into the ground in the fall. They like sunny locations.

Not all milkweeds are beneficial.Avoid Tropical Milkweed (Asclepias curassavica) in zone 8-11. Scientists have reasons to think that caterpillars feeding on tropical milkweed face multiple threats, including unseasonal breeding, putting monarchs at higher risk of disease and reproductive failure. Look for milkweeds native to your area.

A caterpillar eating common milkweed. But don't limit yourself; there are dozens of milkweed varieties to plant, and monarch caterpillars will munch them all.

Monarch butterfly visiting a Joe-Pye weed in flower

For more information on Milkweed Plants.