Outdoor Classroom for September: What’s the Milk in Milkweed? Butterfly Food!

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If you open a green milkweed pod you will find the seeds organized kind of like a pinecone, held together by the milky latex that gives it its name.

Going back to school doesn’t mean learning has to stay indoors. As summer turns to fall, nature provides an outdoor classroom with some fun activities. Right now, milkweed pods are plump and sticky, full of seeds that in a few weeks will dry out and crack open to let loose a cascade of seeds.

A still-green milkweed pod can be taken home and put on a sunny windowsill to try until the seeds are ready to come out.

A still-green milkweed pod can be taken home and put on a sunny windowsill to try until the seeds are ready to come out.

We find our milkweed each August and September on the sunny hilltops of local New England trails where the grass is allowed to grow long and high. (If you go on walks in areas like this – wear long pants and check for ticks when you get home.)

We broke apart a still-moist pod to look at its construction and see the milk, but – depending on where you live – if you go out in the next couple of weeks and search the sunny edges of fields and trails you can pick green pods and take them back to your house or classroom to let them dry out and open naturally to reveal their fluffy seeds. As the fall progresses, you can return to the spots where you found them and see the remaining pods as they’ve turned brown and allowed the wind to draw the seeds out and scatter them.

What is there to know about milkweed? It’s a native perennial plant found in drumlins, prairies and pastures, along roadsides, and on the banks or edges of ponds and lakes. Milkweed gets its name from the milky sap found in its leaves, stems and pods. The milk is made up of latex that contains alkaloids and other complex compounds including cardenolides - all of which serve as defense mechanisms against too-rapid consumption by the creatures that feed on them.

Left on the stalk to dry, the breezes of late fall open the pod and pull the seeds out  and scatter them.

Left on the stalk to dry, the breezes of late fall open the pod and pull the seeds out and scatter them.

Milkweed is a primary source of food for many insects. Their flowers provide nectar for bees, and milkweed is the sole food source for the caterpillars that become Monarch butterflies. Monarchs lay their eggs on the plant, and the larvae feed on it when they hatch. The caterpillars ingest the milkweed, whose toxins linger in their systems and serve as a deterrent to their predators when they become butterflies.  Consequently, Monarch butterflies taste terrible to animals who might otherwise eat them.

Scientists and gardeners are planting milkweed in many locations in hopes of attracting and increasing the population of Monarchs because their numbers have been dwindling in recent years. Scientists are unsure if the numbers are down because agricultural herbicides are destroying the milkweed food source or if climate change plays a role. In any case, if you go looking for milkweed this fall, be sure to leave plenty for the butterflies.

Monarch butterflies wintering over in the trees of Mexico. Photo credit: Maggie Caldwell

Monarch butterflies wintering over in the fir trees of Mexico. Photo credit: Maggie Caldwell

 

 

 

 

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