Brood X: Will Cicadas Harm My Landscape?

If you're like many gardeners, the spring season may be making you nervous for one reason: the emergence of Brood X cicadas.

These periodic bugs are emerging from their 17-year hibernation in some areas of the country this year - and you may be wondering about the impact they'll have on your garden.

But luckily, you don't have much to worry about. These large insects aren’t coming out of hibernation to ravage your garden - rather, they're emerging to mate. And though they do eat and lay their eggs on woody plants, they typically inflict little damage. Their noise might be deafening, but they aren’t dangerous to most of your landscaping.

Now that we’ve put your mind at ease, let’s talk about Brood X, the billions-in-number group of cicadas set to emerge in 16 states in May and June. Here, we’ll answer your most-pressing questions about Brood X and how cicadas impact your landscape:

Why are there so many cicadas this year?

A cicada is a 1.-5-inch winged insect with red eyes. While some cicadas do emerge every year, these ones in particular are called “periodical cicadas,” which means that they emerge every 13 or 17 years, in large numbers. Brood X – “X” standing for 10 – is the largest group of cicadas, emerging every 17 years. This group is also known as the "Great Eastern Brood."

This year, these periodical cicadas will appear when temperatures reach 64 degrees, so the timing of their emergence will vary somewhat from state to state. They will mate for about 40 days, affecting around 35 million Americans.

Brood X is already or will be emerging soon in places including:

• Washington, D.C.
• Bethesda and Baltimore, MD
• Philadelphia
• Cincinnati
• Indianapolis

How long do cicadas live?

Though they are called “annual cicadas,” the answer to this question varies on how quickly an insect matures; the lifespan of periodical cicadas is actually two to five years.

How do cicadas impact your landscape?

Many gardeners wonder what exactly cicadas eat. These insects both drink the sap of and lay their eggs on more than 270 species of woody plants, including oak, ash, maple, cherry, and hawthorn.

Other affected woody plants include:

• Dogwoods
• Redbuds
• Raspberries
• Blackberries

Will cicadas hurt your plants?

The answer is mostly no. However, they can inflict minor damage on young or newly transplanted trees, as well as trees that are already struggling with disease or poor conditions.

Woody plants are sometimes damaged when female cicadas lay their eggs inside undeveloped tree shoots. Some trees, like the mesquite, sometimes lose branches when cicadas make slits in those branches to deposit their eggs.

If a tree is established, cicada egg-laying and feeding aren’t huge issues - just prune away any branches that start to show problems. Less-established trees may die or experience stunted growth after cicada interference, but that, too, is uncommon.

The good news? Because cicadas emerge so infrequently, they are not likely to cause damage that these woody plants can’t make up for with healthy growth in subsequent seasons.

What areas are susceptible to cicadas?

Cicadas do emerge from the ground beneath your lawn, but they won’t damage it. Though they make one-inch holes and three-inch “mud chimneys” in the dirt, that won’t harm the soil. In fact, dead cicadas can add nitrogen to the soil, and their holes provide aeration.

What’s more, cicadas also won’t damage your flowers or vegetables, as they aren’t woody plants. They are also more likely to feed and spawn in established woody areas, more so than in new developments with few trees.

How can I protect my trees from cicadas?

If you are concerned by how your planting and growing season will be affected by cicadas this spring, keep these few considerations in mind:

• Wait: If you haven't planted already, hold off planting young trees until cicada season ends in June. Then, you won't need to worry about a cicada choosing your immature tree and harming it by laying its eggs or feeding from it.
• Wrap: If you’re concerned about the health of a woody plant or have already planted saplings, you can prevent a cicada infestation by wrapping them in netting or plant bags. Cicadas cannot access these plants through these boundaries. Before wrapping, make sure that there are no bird nests in your tree!
• Avoid insecticide: Though cicadas can cause minor damage to some plants and trees, they are mostly harmless as far as insect infestations go - so there's really no need to spray. Insecticides are far more likely to harm the plants themselves, as well as beneficial bugs and other animals in the area.
• Provide extra care: Young or already-struggling trees are much more likely to recover from the effects of cicadas if they’re well taken care of. That means mulching around their roots and watering more frequently if they’re not getting at least an inch of rainwater per week.

Brood X: The bottom line

Despite some anxiety about the impending emergence of Brood X, these large insects are fairly harmless to most of your landscaping. Still, newly-planted trees are cicadas’ favorite snacks and egg-laying spots, so to ensure your peace of mind, you may want to take a few precautions - especially with new plants.

If you can’t hold off planting young saplings, you can protect them with netting or plant bags, along with enough water and mulch to help them thrive. You don’t need insecticides, since these bugs are largely harmless and you want to avoid negatively impacting other plants and animals in the area!

Though cicadas’ chirping may get on your nerves this spring, you’re likely to have worse nuisances in your garden than these guys. The best thing to do? Just wait it out.