Leave the Leaves for Fireflies
Submitted by Johanna Arendt and Jeremy Hull, Travis County Balcones Canyonlands Preserve. Image of firefly on leaves courtesy of Radim Schreiber.
One of the most magical sights of summer is the warm glow of fireflies blinking across the landscape. Many of us have fond memories of catching them and putting them in jars to create living lanterns for the evening. Unfortunately, over the years, they have become more and more scarce. But the good news is we can help bring them back.
Here are some tips to attract fireflies to your yard. Not only will you get to see their beautiful lights on early summer evenings, but they can actually help your gardens. They eat many pests like snails, slugs, and smaller insects. These tips can also save you time and money by reducing the need to rake leaves, buy mulch, and use fertilizer.
- Leave the leaves: Fireflies spend 95% of their lives as larvae in leaf litter and soil, so it’s important not to remove all the fallen leaves. You can set aside part of your property to stay looking natural, leaving the leaves where they fall. According to the Xerces Society, research has shown that lawns actually benefit from a thin layer of leaves. Avoid shredding the leaves, since this can harm the firefly larvae.
- Use leaves as mulch on garden beds: Leaves suppress weeds and retain moisture like shredded wood mulch does, and they add nutrients back to the soil. They also have the added benefit of being a free resource, which you then don’t need to bag up and drag to the curb.
- While it’s best to leave the leaves permanently to break down into soil, if you want to clean up the garden and remove leaves in the spring, try to wait as long as possible before doing so. The longer the leaves stay, the more benefits they provide.
- Don’t use pesticides or herbicides (weed killers), since these can kill fireflies and the insects they eat.
- Plant native trees and native grasses in your landscape. Firefly.org has a list of native Texas plants that are good for fireflies, from asters to oaks.
- Keep non-essential lights off at night, including spotlights on trees. Light pollution is a major factor in the decline of fireflies because it disrupts their mating rituals that rely on females seeing the flashing light patterns of nearby males. For necessary lights, use dark-sky friendly fixtures that focus the light only where it is needed.
- Include water features in your landscape. Fireflies eat the small insects, grubs, and snails that live in ponds and streams (but not in chlorinated pools).
- Be patient, and repeat these steps each year. While fireflies may show up the first year you start, it can sometimes take up to five years.
In addition to helping fireflies, leaving the leaves is essential for important pollinators that help keep the entire ecosystem going. The majority of butterflies and moths overwinter in the landscape as eggs, caterpillars, chrysalides, or adults, and leaves provide them important cover. Leaves also provide a layer of protection for native bees that overwinter in solitary burrows just an inch or two underground.
Rather than being something to rake or blow away, leaves are a valuable resource that will help build soil in your garden and support wildlife, including the magical glowing firefly. Fireflies are also a good indicator of the health of the environment, so seeing their little lights is a sign that your yard is in good shape.
If you’d like to learn more about gardening for fireflies, there are lots of great tips at https://www.firefly.org/. For more on the benefits of leaving the leaves, check out the Xerces Society’s website: https://xerces.org/blog/leave-the-leaves. And for information about the Balcones Canyonlands Preserve, visit our website at https://www.traviscountytx.gov/tnr/nr/.
Image of fireflies on a summer evening courtesy of firefly.org