Liberate Your Lawn & Garden: Four Small Changes You Can Make To Keep Fireflies Happy with Your Yard

Sarah Endriss, for the Shuttle

“Did you get him?” my son yelled.

“No! Do you see her? Where did she go?” my daughter asked.

“He’s over there!”

“Over where?” my daughter exclaimed, turning around and around. “Oh, there she is!”

“Did you get him?”

“Yes! Come look!” my daughter said as she peered into her cupped hands.

Is there anything as nostalgic as a warm summer evening catching fireflies with your kids?

When we first moved to Philly I was surprised and delighted to discover their small flashing lights dancing around our garden, because fireflies for me were synonymous with meadows. Growing up, my grandmother had a large meadow that backed up against our yard, and on any number of evenings my parents could find my brothers and me, empty peanut butter jars in hand, chasing them around the backyard. 

So why are they in my backyard in Philly, and why have they been dwindling in numbers the last couple years?

My initial explanation was that it’s not dark enough; just about all my neighbors keep their backyard lights on during the night. But this is only partially correct. So if that’s not the reason, is it the dwindling amount of native vegetation? 

Well, yes and no. Lightning bugs love native plants, but my back garden is filled with native ground covers, perennials, trees and shrubs. So what gives?

What I’ve discovered is that the reduction of fireflies in my yard may be intimately tied to the rise of the invasive Asian zebra mosquito. Not that the mosquito has anything personally to do with it, but unbeknownst to me, I have been eliminating their habitat every summer because it is also the habitat these god-awful mosquitos love — moist leaves! 

According to the website, whenever we rake leaves and put them out to the curb, we are raking up firefly larvae and throwing them away! When we work to control snails, slugs and worms, we eliminate firefly larvae’s main food source. And when we spray broad spectrum insecticides, especially lawn chemicals, we effectively kill them. 

So as we transition from summer to autumn and the leaves begin to fall, here are a few things we can do to support the firefly habitat:

  1. Leave the leaves in your garden. Leaves protect soil moisture, support soil nutrient development and provide habitat for numerous insects. If your garden has more leaves than it can handle, purchase a leaf chipper and grind them up for mulch to apply to your garden beds. 
  2. Plant native grasses and forbs. Plants help retain critical soil moisture and the birds, bees and butterflies will also thank you. 
  3. Avoid chemicals in your backyard and don’t overmow; not only will fireflies appreciate it, so will your children and pets.
  4. Turn off outside lights at night and advocate for local “Dark Skies” policies. Not only will fireflies then find each other, but our children’s children may also have the privilege and joy of chasing them on a summer evening.