Fueling the Migration

The migration story of the monarch butterfly is one that seems to resonate with a lot of people. The story of plucky insects making their way from Mexico to Canada and back again is inspiring, all along the way depending on the availability of a native plant called milkweed (Asclepias sp.) to make the next generation.

Monarch populations have sharply declined in the last decade due to lack of milkweed and gardeners all over have responded by planting more milkweed to help them.

Milkweed is only part of the story. Last week I wrote about the native plants that we might choose to put in our gardens for fall residents and especially migrating monarch butterflies. They are the nectar plants. These plants provide the fuel that adult butterflies need.

2018 Migration Photo from Journey North

Yet, as hard as we try, our gardens can’t do it alone. I know what most residential gardens look like by now, and there are not a lot of flowers left. The reported migration numbers show a lot of butterflies still north of us. What are they going to eat? The answer lies in the flowers of the goldenrod (Solidago) and aster (Symphyotrichum) plants that line our roadsides, fill up vacant fields, and populate the spaces beneath our power lines.

Late blooming field of goldenrod (Solidago altissima)

These are the messy, tangled places that some people disparage. They are lifesavers to these butterflies. Roadside populations can outnumber what we do in our gardens. I look at the asters on the side of the road, in ditches and messy places, and cheer: “Go, tiny white asters, go!” I see late blooming fields of goldenrod and silently thank the landowner who mowed it mid-summer, producing this late flush of fresh flowers just in time.

How can we help keep these roadsides going? Knowledge is the key, whether you have it or you share it:

• If you are the owner of places like these, don’t mow them until the flowers are done (or better, wait until just before new growth starts in the spring so that the flower seeds can feed winter birds).  Resist the urge to ‘tidy up’ for human aesthetics. Want to tell people it's deliberately left unmowed? Post a pollinator habitat sign.

• All of us can educate others on the importance of these late flowers. Let your city/county/state road departments know that these areas are important. They can mow a ‘safety strip’ close to the road and leave large areas untouched (and that could save them money!) until spring. Pollinator health can be a part of their community goals. This communication from the Federal Highway Administration written in 2017 might be a good start to encouraging them to understand that managing roadsides can be “a significant conservation opportunity.”

• Utility companies are responsible for large areas of vegetation in and around power lines. They often contract out for vegetation control but they can dictate the schedules of the work, ask for cutting over spraying (cutting allows perennials like goldenrods and asters to regrow in the same year), and communicating in general that they are trying to support pollinator health in their management practices.

Mow strip (Photo: Jennifer Hopwood, Xerces Society)

Support our roadsides and fall-flowering areas of wild native vegetation. Recognize that there are insects that depend on them (and actually birds too). Just like planting milkweed in our gardens, our support of these places is part of what we can do as humans to help restore some of the balance disrupted by our own buildings and infrastructure.