Skip to content

GARDENER'S NOTEBOOK | Gardening for the monarch butterfly

E very year I enjoy walking down the road and checking the wild milkweed for monarch eggs and caterpillars.

Every year I enjoy walking down the road and checking the wild milkweed for monarch eggs and caterpillars. If I’m lucky enough to find some, I whisk them off to my butterfly nursery where I enjoy watching them grow through the different stages until they morph into little orange beauties, a practice I hope to share with my son when he’s old enough to understand. I currently have eight caterpillars in my small nursery, and as I watch them contently munch away at the leaves, I wonder how much longer I’ll be able to enjoy them this way. This year, monarchs have reached a new, more critical level of endangerment, which potentially threatens my dreams of raising monarchs with my children.

Monarch butterflies are not your average butterfly. The first monarchs you see in spring have travelled some 5000 kilometers from the mountain forests of Mexico. Their arrival in Canada coincides with the growth of milkweed, upon which they quickly lay eggs to start the summer’s new generations of butterflies. Each summer, there are about three to four generations of monarchs before a special autumn generation is hatched. This autumn generation (aptly named the Migratory monarch) is triggered by reduced daylight, cooler temperatures, and even the age of the milkweed the caterpillars feed on.

A new monarch comes into being. From an egg grows a caterpillar, which becomes a chrysalis. The exterior of the chrysalis is the exoskeleton, or skin, of the pupa. Eight to 12 days later, the monarch emerges. In 2018 this caterpillar chose a Japanese daisy in a Fonthill garden for its transformation, after feeding on nearby milkweed. Chrysalises can hang from nearly any plant or object. YASMIN TERCINTA

These autumn monarchs are special: they are born in a state of reproductive pause, meaning they have a much longer lifespan than the earlier generations. Your average summer monarch has a short lifespan of only two to six weeks, whereas the Migratory monarch can live seven to nine months! The migratory generation travels all the way to Mexico by the end of October, arriving at their winter hibernating grounds around the Mexican holiday Dia de los Muertos, on November 1 and 2. A traditional belief among Mexicans is that the return of the monarch represents the annual return of the souls of their departed family members.

Once monarchs reach the mountains, they will then seek out oyamel fir trees to latch onto and spend the winter in a state of hibernation. As days begin to lengthen again in the spring, they wake from their hibernation and begin the long journey back to Canada and the northern United States to reproduce and start the whole cycle over again. A truly remarkable feat for a butterfly!

But, sadly, there are several factors that are making it particularly hard for monarchs now. Deforestation in Mexico has reduced their winter hibernation grounds, and along their migration routes through the United States and Canada the loss of milkweed and feeder plants has further caused butterfly populations to plunge. This coupled with pesticide use and inclement weather patterns such as late winter storms have decreased the monarch population by more than 80 percent in the last two decades.

Even if habitat conditions are perfect, monarchs still succumb to predators and disease much like any other living thing. It is estimated that only 5 percent of monarch eggs make it to breeding adults, so the odds are definitely not in their favour. Ants, spiders, wasps, and even praying mantis are the main predators of both young caterpillars and mature butterflies. Surprisingly, even older monarch caterpillars can accidentally eat smaller caterpillars or eggs if they happen to be on the same leaf. Yellowjacket wasps are particularly hard on monarchs as they are known to attack adult monarchs that are hanging to dry shortly after emerging from their cocoons.

Even if habitat conditions are perfect, monarchs still succumb to predators and disease much like any other living thing

Despite the bleak outlook of the monarch butterfly, and all the challenges they must face just to reach adulthood, they can bounce back with just a little help from us.

Monarchs can only reproduce on milkweed, and, luckily, there are many different varieties of milkweed that you can add to your gardens which they will happily munch on.

The aptly named Butterfly Milkweed, which flaunts bright orange pompom flowers on shorter bushier plants, as well as Swamp Milkweed, a taller variety with bright pink flowers, are just a couple of examples. Both these varieties are available at local garden centres. Whorled Milkweed, White Milkweed, and Purple Milkweed are other native varieties that you can keep an eye out for. Common Milkweed (which is frequently seen in ditches around Pelham) is also very attractive when it’s in bloom, with its soft pink flowers and fuzzy leaves. Milkweed can spread easily if left unchecked, which is great for a wild field, but not ideal if you like to keep a tidy garden. If you’d like to limit your milkweed spread, just clip off the seed heads when you see them starting to ripen in late summer.

A monarch stops in for a snack on this zinnia bloom. PETRA PAZOUR

Planting milkweed is essential for caterpillars, but planting feeder plants are equally as important for the adult butterflies and other pollinators. It’s the nectar gathered from these feeder plants that give monarchs the energy to migrate and make it through the winter. Monarchs particularly love Purple Coneflowers, Black-eyed Susans, and Liatris species, but they will also visit other late summer flowering plants such as Marigolds, Zinnias, Lantanas, Sunflowers, Cosmos and Petunias.

Goldenrod is another preferred plant and an excellent source of nectar in the late summer and autumn, coming into bloom to coincide with their winter migration. Contrary to popular belief, goldenrod is not responsible for seasonal allergies. The real culprit is ragweed, which often grows in the same places as goldenrod but is more inconspicuous with non-showy flowers. Since goldenrod is easily spotted, and so prolific come late August, it tends to get the blame, and also the weedwacker. Goldenrod is an essential food source for monarchs on their way to Mexico as well as other pollinators preparing for the winter, so if you have some growing, consider keeping it around.

Gardening is a rewarding hobby not only because you can grow beautiful (and tasty) things, but in doing so you can also help pollinators at risk like the monarch butterfly. You’ll quickly find that by planting and maintaining a garden for these orange beauties, you’ll also be attracting other neat pollinators to look at and admire!

Aleksia Shoalts is a Director for the Pelham Garden Club and also writes a blog about gardening and DIY projects. Have gardening questions you want answered? Contact her at [email protected]