They say, if you build it, they will come. That really clicked for me when I saw a monarch caterpillar lay an egg on a milkweed leaf in my garden. These plants were the descendants of seeds I started in a damp paper towel in my refrigerator. I had sown, and the monarchs landed.

I’m familiar with monarchs, Danaus plexippus, from my own childhood. A patch of common milkweed in the meadow reliably produced striking yellow-and-black caterpillars which turned into pupae like filigreed jade earrings before becoming resplendent monarch butterflies. There were so many we thought nothing of bringing them in for show-and-tell – mostly, to show how pretty they were – but my reacquaintance with monarchs would tell me a bigger story about the power of plants. 

The habitat I grew up in, heavily forested, punctuated by man-made clearings and minimal sprawl, is ideal for monarchs and milkweed. But for much of the monarch’s migration path from Mexico to Canada, a combination of habitat loss as well as pesticide and herbicide use have contributed to steep population decline for both insects and plants. Pollinator gardens, areas intentionally planted for bees, butterflies, and birds, have been deemed a way to restore the presence of these organisms. It stands to reason, then, that no North American pollinator garden is complete without an Asclepias.

The relationship between Asclepias and monarchs is existential: baby monarchs, in the form of caterpillars, can’t eat anything but Asclepias’ leaves, buds, and stems. After becoming butterflies, the winged insects sip only nectar for the rest of their lives, which can come from various flowers, especially the Asclepias family. I wanted my milkweed patch to include at least two types, and so I started trying to grow the common milkweed of my memories for the butterflies of my dreams.

Before I came to live in Peekskill, I didn’t know that monarchs could subsist on any other Asclepias type but the common milkweed, Asclepias syriaca. (I now know that there are dozens of types of this plant that can grow in the US.) I didn’t recognize her sister, Asclepias tuberosa, until I trimmed a stem and saw the familiar white sap reminiscent of school glue. Butterfly milkweed (tuberosa), also known as butterfly weed, has sprays of stunning orange flowers that float in the middle heights of a meadow or sunny garden and spread only through seed. The syriaca version spreads aggressively through both rhizomes (underground stems) and seed and grows up to 6 feet tall. (Be prepared to stake this rangy species as it will flop without a strong underpinning to mimic the dense meadows it thrives in.) Syriaca’s blooms are a vibrant purple and smell heavenly, broadcasting its presence to a number of pollinators besides the monarch with wafts of vanilla that intensify as night falls. 

Cultivate patience to grow Asclepias: these are native perennials that need to be stratified (that is, kept cool and damp to signal seeds to germinate) for at least a month during the winter. Winter sowing is a great way to achieve this, but I started my first Asclepias syriaca and tuberosa in wet paper towels stowed in a plastic bag. Once six weeks had passed, I planted them in small soil cells and put them under grow lights. Germination wasn’t great, but the descendants of those little stragglers have now populated my front garden to the point where I’ll be able to transplant many to create a pollinator waystation in the backyard. They’re part of a low-care plant family: all they needed was a sunny spot and an occasional drink during their first year.

It was upon these two types of milkweeds in my garden that I knowingly hosted one generation of monarch butterflies last May 2024. The project began once my children and I sighted a monarch, watching it alight on milkweed plants in the garden. When the butterfly had departed, we snuck a peek at the leaves–unmistakably, eggs!

From there, I watched as the eggs – about fourteen in all – turned into their first and second instars (“instar” meaning a stage in a maturing insect’s development between moltings) and more easily detected by the frass (a polite word for insect poop) they left behind. There are five instars between a monarch caterpillar emerging from its egg to when it’s large enough to turn into a butterfly. My family delighted in locating the ever-larger cats (“cats” meaning “caterpillars,” from someone who’s in the know about butterfly development) and then couldn’t find them anymore. A careful search turned up a single pupating individual on the side of the house, but the rest were so well hidden that we just had to wait until they appeared again as butterflies. Monarchs will travel far from the milkweed to undergo their transformation away from predators.

You can imagine our surprise when we came home to find that single hanger-on had vacated its chrysalis, with no butterfly in sight. It was silly, but the story I had constructed – building the monarch’s nursery, witnessing the growth from single egg to becoming the equivalent of caterpillar toddlers, kids, and teenagers – was already so available for our human awareness, it seemed impossible we’d miss the moment it transformed into an adult who would fly away.

It may have been a lie, but we dubbed the next butterfly we saw “our” monarch. At any rate, the gardener in me really got it: plant it, and they will come.

And so this winter, I started a new type of Asclepias – swamp milkweed, or A. incarnata. This milkweed, like her sister A. tuberosa, has the tidier habit of spreading only via seeds, and growing to a mere five feet tall. I look forward to seeing the next generation of monarch cats growing on all the milkweed I can find this summer, and wish many monarch sightings on us all!

Send pictures of your favorite pollinators and plants to Lucy at [email protected], and stay tuned for summer garden tours!