Summer is officially here. For many Americans, that means blankets of grassy green for kids to play in, or families to picnic on.

There are an estimated 40 million to 50 million acres of lawn in the continental United States — that’s nearly as much as all of the country’s national parks combined. In 2020, Americans spent $105 billion keeping their lawns verdant and neat. But our grass addiction comes at an environmental cost.

According to the Environmental Protection Agency, maintaining those lawns also consumes nearly 3 trillion gallons of water a year as well as 59 million pounds of pesticides, which can seep into our land and waterways.

Department of Transportation data shows that in 2018, Americans used nearly 3 billion gallons of gasoline running lawn and garden equipment. That’s the equivalent of 6 million passenger cars running for a year.

As these issues are becoming more prominent in climate change discussion, there are steps you can take to more sustainably manage the impact of your lawn. The Washington Post’s garden correspondent Adrian Higgins has covered everything from using organic fertilizers (or making your own from compost) to avoiding pesticides. The transition to electric lawn maintenance equipment is also well underway.

But how we care for our lawns is secondary to the amount of lawn we have in the first place, experts say. Having less grass and more plants is among the most important factors in keeping a yard eco-friendly.

“Lawn, ecologically, is dead space,” said Doug Tallamy, an entomologist at the University of Delaware and author of “Nature’s Best Hope: A New Approach to Conservation That Starts in Your Yard.”

The solution, he says, is ultimately less lawn. He recommends people aim to cut the amount of turf grass in their yard in half. But getting there, he says, will take a shift in culture that goes far beyond just using an electric mower.

America’s infatuation with grassy expanses dates back to the Founding Fathers. Thomas Jefferson cultivated a lawn — previously a fixture of the European aristocracy — at his Monticello estate. By the second half of the 20th century, as the middle class grew, bought houses and spread into the suburbs, lawns had become a staple of Americana.

But, Tallamy insists, change is possible. “You can be an important part of conservation,” he said. “You aren’t powerless.”

Laying down mulch is one place to start. It quickly kills grass and offers a blank canvas for planting.

“If you have lawn under a mature tree, convert it to a mulched area,” suggested Kathy Connolly, a Connecticut-based landscape designer who recommends about six inches of raw, arborist, wood chips for the job. Connolly also recommends converting some of your lawn into paths, rock gardens or other features. “Ecologically, though,” she said, “the best thing to do is plant native trees and shrubs.”

Invasive plants, Tallamy said, “are ecologically castrating the land around us.” Native plants, on the other hand, often have deep root structures, making them good for storing water or providing drainage. They have also co-evolved for local conditions.

The inclusion of native plants could look like cold-tolerant plants where temperatures dip or cactuses that need less water in arid regions. Eric Braun, the water resources manager for the town of Gilbert, Ariz., is quick to emphasize that water-friendly landscapes, also known as xeriscapes, don’t have to look like moonscapes.

“Xeriscape doesn’t mean one saguaro and a cow skull. It can be very lush and inviting,” said Braun.

“The number one thing was showing people that it can be a beautiful landscape.” he said. And when they realized that they didn’t have to spend every Saturday mowing it, that really started to change people’s perception.

More broadly, Tallamy said native landscapes can help refocus our gardens on the ecological purpose of plants, which is to produce food. Plant energy gets passed up the food chain, often via insects. But many insects only eat one native plant species, or group of related plants. So, if we are planting nonnative plants, that food doesn’t necessarily transfer from creature to creature, and the ecosystem can stall.

Tallamy said native flora better supports native fauna and, as a result, helps combat these declines. Tallamy is a fan of oak trees, which come in 91 native species, grow almost everywhere in the country and attract caterpillars, a key species for supporting other wildlife — to raise a clutch of chicks, a pair of robins needs between 6,000 caterpillars and 9,000 caterpillars in just 16 days, Tallamy said.

“It’s not that we’re being nice guys to nature,” Tallamy said. “We need this, or we’re in big trouble.”

Others put less emphasis on nativity, and more on the diversity of species and types of plants in a yard.

“Yes, we want natives but let’s be inclusive and not exclude plants that have come from somewhere,” said Juliet Stromberg, a professor at Arizona State University, who was one of more than a dozen ecologists who wrote a letter arguing that a plant’s origin is less important than its environmental impact.

“What I would suggest is just loosening the reins a little bit,” she said. “If you’re bringing in the plant that’s the same genus, the insects are going to be fine.”

Casey Reynolds, the executive director of Turf grass Producers International, a trade association for grass farmers, argues that grass can be a great option, especially in urban or suburban environments. One of the benefits, he says, is that lawns provide an area for people to play.

“I would never tell people to plant grass everywhere,” he said. “[But] I can’t enjoy my lawn if it’s made up of shrubs.”

The value of grass falls on a continuum, said Mark Hostetler, an urban ecologist at the University of Florida. On one hand, wild, native grasses are wonderful carbon sinks that support biodiversity. But when grass is maintained, he said, it loses many of its environmental advantages.

Hostetler said manicured lawns are “better than cement …(but) ecologically horrible.” Cutting the grass, he explained, rereleases the carbon that was stored in the clippings and halts the growth of other plants that may be coming in. The emissions from mowers, fertilizers, water and other types of lawn care further offset environmental gains.

Whether you choose native or nonnative replacement plants, cutting back your lawn is an admittedly difficult undertaking. Plants cost money, and landscaping takes time. Outdoor space of any sort is a luxury in many urban, low-income and minority communities — let alone the ability to prioritize plants.

“I understand that changing your landscape is a pain in the neck,” said Jim Kleinwachter, the “Conservation@Home” program director at the Conservation Foundation. But he offers an upside: “You’re going to have color through the summer instead of one thing.”

Plus, residents often revel in livelier gardens. “People love butterflies and birds,” Kleinwachter said. “At the same time, the other pollinators will come in under the radar.” That, in turn, means more flowering plants, about three-quarters of which require pollination.

Wading through the differences between native and nonnative plants — say Japanese wisteria (invasive) vs. American wisteria (native) — may also seem daunting. While a quick Google search can often help, state and local nature and gardening organizations are another useful resource. The National Wildlife Federation also has a native plant finder curated by Zip code.

“The biggest question we get is ‘Where I can find these native plants?’” Mary Phillips of the National Wildlife Federation said. She says local nurseries maybe able to help. This spring, the National Wildlife Federation launched a “Garden for Wildlife” shop, which sells native plant bundles such as “Pollinator Power” and “Monarch Munchable.”

The good news for monarchs, and other insects, is that the native plant movement is catching on. From 2019 to 2020, Phillips said the number of people planting and certifying their wildlife gardens as National Wildlife Federation certified wildlife habitats doubled. Many more are opting for less lawn.

Laurie Silvia, a homeowner in Old Lyme, Conn., said she and her wife used to spend hours each week on lawn care — maintenance that was getting more difficult with age. So, a few years back, the couple decided to make a change.

On a budget, Silvia found free leaf mulch, collected cardboard, and started to cover up the grass. She refilled the space with plants that she swapped with friends and neighbors. She also made part of her backyard into a meadow.

“Most of us grow up with the (notion) lawn has to be green and has to be perfect,” Silvia said. “The hardest thing is letting go of these ideas we have.”

Today, she estimates she has about 80 percent less lawn than before, which has cut mowing time dramatically. She says it has attracted a plethora of wildlife. “We don’t have go on a hike to see nature; we’re bringing it into our yard,” Silvia said. The bunnies are abundant now, she said. The birds are bountiful. Foxes and turkeys have also come through for the first time.

“I wish they would get off their lawn mowers and find a different way to enjoy their properties,” Silvia said, encouraging others to follow suit. “Just let yourself go and be free to color outside the lines.”