Auckland’s love affair with lawns has a hefty bill

By Rebekah White

Olivia Rooke-Devoy’s map of Auckland is covered in splotches of green.

These are all of its lawns, and they carpet around a third of the city.

On average, up to 20 percent of urban areas in New Zealand is lawn – and they come with substantial costs, her research finds.

In Auckland, people spend $131 million every year on lawns, according to Rooke-Devoy’s analysis. That doesn’t include council spending on mowing, irrigating, weed-killing, fertilising and maintaining areas of public land: berms, traffic islands, golf courses, sports fields.

Rooke-Devoy, a PhD candidate in the Faculty of Science at the University of Auckland, has spent the past decade investigating whether there are better options than grass for New Zealand lawns: cheaper, more climate-friendly alternatives.

Mowing creates a surprising amount of carbon emissions.

An Australian study found lawn mowers were responsible for 5 percent of a region’s carbon dioxide emissions.

A separate report found that caring for lawns across the entire United States is responsible for roughly the same emissions as the city of Los Angeles and releases 230 million cars’ worth of PM2.5: tiny, toxic particles that can penetrate the lung and bloodstream.

Then there are more direct health effects.

About 7000 people per year in New Zealand injure themselves mowing the lawn at a cost of $12.6 million, according to ACC.

“I guess people think, ‘Well, me mowing my lawn isn’t going to have any impact,’” says plant ecologist Bruce Burns, an associate professor at the University of Auckland and Rooke-Devoy’s PhD supervisor.

“It’s just small pieces of lawn, but they add up to a substantial amount of area.”

Burns and Rooke-Devoy see all these lawns as an opportunity.

“Especially as we’re losing green space because we’re having to intensify,” says Rooke-Devoy.

“The green spaces we have need to be working harder. So how do we manage [them] better? And the easiest answer is, well, can we reduce mowing?”

The problem of the ‘antisocial’ lawn

There’s one obvious solution: just let the grass grow.

But it’s not a socially acceptable one, as Rooke-Devoy learned first-hand when she caught her neighbour sneaking out at night to mow the overgrown berm outside her Auckland house.

“Obviously I was letting down the neighbourhood,” she says.

The situation inspired her to study lawns – and to challenge how people think about them.

“What we’ve found is that lawns have a distinct place in our social fabric,” says Burns.

“People often look at how your lawns are maintained as an indicator of your contribution to society or a reflection of your character.”

Lawns translate into financial value as well as social capital, says Rooke-Devoy.

Studies in the United States found that more manicured lawns are connected with increases in house values of 7 to 17 percent.

“So your house price is correlated with the quality of your lawn out the front,” says Rooke-Devoy.

The key to a wilder lawn, says Rooke-Devoy, is to incorporate clues that it’s still maintained.

It’s an idea called Cues to Care, developed by landscape architect Joan Nassauer.

What that involves: “Mowing edges, signage, seating, sometimes a path, basically showing that there’s a human hand in what’s happening,” says Rooke-Devoy.

“It shows that it’s intentionally managed, it’s not just neglected,” says Burns.

He also advises continuing to mow grass around homes—long, dry grass near houses is a fire hazard—as well as cutting down meadow-like lawns before the end of summer to avoid a build-up of dry fuel.

Are meadows better for biodiversity?

In Europe, public spaces increasingly incorporate wildflower meadows alongside mown areas.

New Zealanders often ask Rooke-Devoy if they can turn their lawn into one of these.

In Hamilton and Wellington, no-mow trials in public parks found that biodiversity boomed: monitoring tracked an increase in vegetation, flowers, insects, and even visitor numbers in parks, as people came to see these new areas.

Aucklanders and Northlanders, however, face an extra challenge: Rooke-Devoy’s surveys of city lawns found that 97 percent of them were dominated by kikuyu, an invasive grass from east Africa.

“It’s taking over Auckland,” she says. “Like an ecosystem destroyer.”

Rooke-Devoy’s research found that, in these places, the result of not mowing was just more kikuyu—unless it was totally removed in the first place.

“It’s just the reality of being such a perfect climate for these invasive plants. So if you’re looking at low-mow on a kikuyu lawn, it’s for the reduced costs. You’re not going to see a change in what’s growing there.”

In subtropical Auckland and Northland, where kikuyu thrives, Rooke-Devoy says that areas of low soil fertility provide more opportunities for gardeners.

When she removed kikuyu from low-fertility study sites, they became more ecologically interesting: a native orchid popped up in one.

These might be places where topsoil has been removed, that have been lawns for a long time, or where the soil is clay.

One example in Auckland is Waikumete Cemetery. The soil, a former gumland, is naturally low-fertility, and there, flowers left at gravestones have self-seeded, creating a meadow. Now, the cemetery is only mown once a year.

“It’s a well-known wildflower area,” says Burns.

Perhaps a little less mowing is in order

While there isn’t a prescription that suits every lawn, New Zealanders stand to benefit from a little less mowing.

“We think we could pull back on the highly managed areas,” says Burns.

Burns and Rooke-Devoy advocate reassessing mown areas, and looking for some which could be left to grow wild, or mown less intensively.

“It has to be context-specific, site specific—selecting areas that would work,” says Rooke-Devoy.

“You’d have certain lawns which are highly managed, but you might have areas around the edges where you allow it to be wild,” says Burns.

Rooke-Devoy cautions that wildflower meadows don’t remain photogenic through the seasons, after the spring and summer flush of flowers, so people need to adjust expectations for all their lawn’s variations.

“The pictorial meadow is a very transient thing,” she says.

“It’s accepting that kind of wildness, where maybe it’s not going to look picture-perfect through the year.”

She’s very interested in ‘plant blindness’, or the difficulty people have in distinguishing between different species in the mass of green growing things.

“We treat lawns like they’re carpets,” she says.

“We don’t look at what’s growing there.”

She’d like people to start seeing their lawns as part of nature and paying attention to what’s happening in them.

“So actually, looking and going, ‘Okay, there are 17 different plants growing here, and they’re all doing different things,” she says.

“Your lawn’s constantly changing, you know, plants arriving and leaving. They’re fascinating little spaces.”

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