Cicadas and Your Garden

Cicadas and Your Garden

By Michael Jenkins

Spring 2024 is shaping up to be a strange time across North America. Last week brought us the eclipse, the weather has been uneven in parts of the US and Canada, and now we’re moving into May with new excitement to come. In particular, gardeners and landscapers in the eastern parts of the US are focused on cicadas. These insects are about to have a population explosion, starting in late April and continuing through June/July of this year. With trillions of them expected to hatch over the next weeks and months, many of us are concerned about how cicadas will affect our plants. So, let’s dig in and learn a bit more about cicadas and your garden and what—if anything—you need to do about them.

What are Cicadas?

Cicadas are insects, in this case of the superfamily Cicadoidea. There are broadly two kinds of cicadas: annual cicadas emerge every spring, and are common in much of North America. Periodical cicadas do things a bit differently—they nest in trees and lay eggs there, with the hatched larvae moving underground. The young emerge again every two to 17 years, depending on species. The young cicadas, called nymphs, spend the intervening years underground eating the roots of plants and trees; we’re told they have a special preference for perennials. This reproductive habit may seem unwieldy, but it allows them to conserve their energy, avoid predators, and then execute their entire reproductive cycle all at once.

What this means for us is that we’ll see trillions of these large, loud insects emerging in large broods over the next few weeks and continuing into summer. The periodical cicadas we’ll encounter are of the Magicicada spp type. These insects are typically 1-1.5 inches/2.5-4cm long, with reddish eyes and dark colored bodies. While they may look intimidating to those of us who don’t care for bugs, the reality is that these insects are harmless to humans and pets. You’ll most like hear the adult cicadas, who make a loud humming or buzzing sound as part of their mating rituals. You will likely see the nymphs and the dark-colored cast skins they leave behind as the molt into their winged adult state.

Will Cicadas Eat My Plants?

Let’s start this section with a “bottom line up front”: cicadas won’t eat your veggies or flowers. They’re generally not interested in most plants humans cultivate, and pose no threat to them. Even the nymphs, which spend years underground dining on plant roots, do no real damage to the plants and shrubs in our garden spaces.

The only potential trouble with cicadas comes from the way they lay their eggs. Female cicadas lay their eggs in trees, by making a small slit in the underside of a branch and depositing the eggs there. Then the eggs hatch into young nymphs, which move to the ground and live their until it comes time for them to emerge and start the cycle again. The nesting process doesn’t pose any threat to mature trees, but very young trees may suffer some limb loss or in extreme cases even death. We recommend wrapping netting around young trees and shrubs to give them a bit of protection from cicadas. Any good light netting small enough to keep bugs out but light enough to not hinder the plant’s growth will do.

What Should I Do to Keep Cicadas Out of My Garden?

Cicadas pose no real danger to plants or animals—or humans—so there’s no need to worry. As we’ve suggested, protecting young trees might be helpful but there are no other concerns. You may wake up some mornings to find that the ground is covered with the dried molted husks or skins from the nymphs. These can be a little annoying as they crunch underfoot, but they’re easy to sweep or rake up and add to  your compost pile. Likewise later this summer when dead cicadas start appearing, you can add them to your composter for a fertilizer boost.

Please do not use pesticides on cicadas—they’re both unhelpful in deal with the large numbers of insects in question and they can be harmful to other creatures in the environment around them. Cicadas are a natural part of the ecosystem in which we live, and this summer will be an amazing chance to see a really fascinating natural phenomenon up close. In addition, cicada nymphs help loosen the soil and provide free fertilizer while also increasing water drainage. So not only do cicadas not hurt anything, they actually help our gardens and lawns thrive!

We hope this blog helps allay some of your fears or concerns about cicadas—even in the large numbers expected this year, these insects are harmless. Take a chance to enjoy their singing, marvel at the molted husks they leave behind, and enjoy this experience for what it is. Oh—and send pictures of cicadas in your garden spaces. We love to see what you’re up to!

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