Does nature need cities?

Monarch butterflies are picky eaters. They’re also some of the most remarkable long-distance travelers of the insect world. That’s not a great combination, especially when the plant they need to survive — milkweed — is getting thin on the ground. It’s one reason why, in the past 25 years, the eastern population of these once-common butterflies has declined by more than 80 per cent. 

Native plants inhabiting wetland habitats in rural areas — DUC projects included — are known to attract pollinating insects like butterflies and bumblebees. But Abigail Derby Lewis thinks cities, like her hometown of Chicago, Ill., can also help the monarchs on their way.  

Urban green spaces can help monarch butterfly conservation 

Derby Lewis is the senior conservation ecologist at The Field Museum in the Windy City.  

“Historically we have written off urban places as being devoid of any kind of opportunity,” she contends. “There’s also an assumption that people in cities don’t care and are disconnected from nature. Neither of those are accurate.” 

So, how can Chicago boost the butterflies? The city is right on the monarchs’ central flyway as they make their four-generational journey from Canada and the U.S. down to the high mountains of Mexico and other southern overwintering sites. All along that flyway the butterflies need milkweed to lay their eggs and for their caterpillars to eat. An additional 1.8 billion more of these host plants than there is now is needed to stabilize the monarch population and reduce their risk of extinction. 

Derby Lewis thinks a lot can be planted in cities.  

Where can we grow milkweed in our cities? 

Where in the concrete jungles would all that milkweed grow? According to Derby Lewis, possible city locations include: 

• vacant lots
• school yards
• corporate campuses
• golf courses
• cemeteries
• hospitals
• rooftop gardens

DUC’s consulting arm — Native Plant Solutions — incorporates certain milkweed species around naturalized stormwater retention pond projects in southwest Winnipeg to increase the biodiversity and health of these wetlands. 

Planting milkweed in backyards can help butterflies and homeowners

Providing monarchs with meals doesn’t have to be just the responsibilities of corporations, local governments or organizations. Derby Lewis advocates homeowners planting milkweed, native grasses and other plants attractive to pollinators. Here are some of the advantages: 

• Many of those plant species need less fertilizer than lawns, have deep, soil-binding roots and can hold a lot of moisture — which beats watering the grass in hot weather.
• If you plant it, they will come. Milkweed is the only plant where female monarchs can lay their eggs. Put some milkweed in your backyard or balcony planters, says Derby Lewis, “and the likelihood of seeing monarch eggs on those leaves in the next year or two is high.”
• By providing an urban food court for pollinators, you’re not just creating important habitat for monarchs, you’re planting the germ of the idea with your friends and neighbours.
• Taking action in your own backyard allows you to see how your activity connects to all the other conservation initiatives undertaken by governments and organizations like DUC.

Recommended native plants for pollinators

Want to include some native plants in your yard to help prolific pollinators like the monarch? Staff at DUC’s Native Plant Solutions suggest these options: 

• Swamp milkweed: As you might guess from the name, this milkweed likes to grow in wetter areas. It grows to about four feet tall with multiple large reddish pink flowers. 
• Whorled milkweed: This species is shorter in stature, with white flowers and fine textured leaves.  
• Meadow blazing star: While it doesn’t provide food to the monarch’s larva stage, the flowers of this plant are good sources of nectar for adult butterflies.  
• But just say no to common milkweed! Avoid using common milkweed — it’s considered a noxious weed in some provinces and can be toxic to cattle. It has aggressive spreading roots and can take over a small garden.  

Learn more about urban butterfly conservation at The Field Museum’s website.