DOBBS FERRY, N.Y. » They have been burned, blown into piles, raked into bags and generally scorned by homeowners everywhere. Fall leaves – so pretty on the trees, such a nuisance when they hit the ground – have long been a thing to be discarded. But now some suburban towns are asking residents to do something radical: Leave the leaves alone.

In the past few years, lawn signs have sprouted in this Hudson River village and across Westchester County, proclaiming the benefits of mulching the leaves in place, rather than raking them up and taking them away. The technique involves mowing the leaves with special mulching blades, which shred them into tiny bits. That allows them to quickly decompose and naturally feed lawns and shrubs.

Officials are encouraging the practice for its cost savings: Westchester spends $3.5 million a year on private contractors who haul away leaves in tractor-trailers and bring them to commercial composting sites in places like Orange County, N.Y., and Connecticut. At the same time, environmental groups and horticulturalists are praising the practice’s sustainability, devising slogans like "Leave Leaves Alone" and "Love ‘Em and Leave ‘Em."

Karen Engelmann, a novelist in Dobbs Ferry, used to rake up the leaves on her half-acre property, which is laced with old oak trees. She once had 120 bags of leaves lined up at her curb to be taken away by the village. "I wondered, ‘Where do these go?’" she recalled. "I thought it was odd that there wasn’t an alternative, that there wasn’t someone saying you might want to think about how the planet functions."

It turned out that her landscaper, Tim Downey, had started experimenting with the new technique. On an unseasonably warm afternoon last week, he navigated his mulching mower over a thick pile of leaves, producing a fine layer of confetti. Downey said the mulched leaves improve the soil’s water retention and provide critical nutrients, reducing the need for fertilizer in the spring.

"It’s utterly insane to be driving tractor-trailers 90 miles away," said Downey, owner of Aesthetic Landscape Care in Hastings-on-Hudson. "My feeling is that if I’m taking away your leaves, I’m stealing from your property."

Indeed, commercial firms use fall leaves as a raw material to produce mulch and compost for sale to nurseries. But towns and counties pay to get rid of them. In Westchester, for instance, the county pays a private hauler about $40 for every ton of leaves that it takes away. Municipalities pay the county $15 a ton. So a county resident is ultimately footing the bill through both municipal and county taxes.

County officials say mulching leaves in place not only improves soil quality, but also has other environmental and safety benefits for communities. Piles of leaves left at the curb can clog storm drains; the nitrogen and phosphorous leaching from decomposing leaves heaped by the street can also more easily enter the drains and harm local rivers. Additionally, leaf piles constrict already narrow streets and can conceal children.

Westchester County appears to be in the vanguard on leaf mulching, but there are nascent steps in New Jersey and Connecticut to reduce leaf collections. For the first time this fall, the city of Englewood, N.J., which estimates that between overtime, equipment maintenance and fees, it spends $200,000 a year on leaf removal, is pushing the idea through email blasts and a newsletter. "Leaves clog storm drains, they’re slippery and they can catch on fire when cars park on top of them," said Kevin Lake, a member of the city’s Environmental Commission.

Public service announcements and mulching workshops in Westchester have nudged homeowners to buy mulching attachments for their mowers and impelled landscapers to offer the service. But it is not always an easy sell.

For those who do it themselves, the mulching attachments can be cumbersome. And then there is the aesthetic factor. "People want everything removed from their lawn, and landscapers just want to keep their customers happy," said Marianne Petronella, director of resource management for Westchester County’s Environmental Facilities Department. "I know some residents would never do mulching in place. They want to keep up with the Joneses."

Stephen J. Edwards, the director of public works in Westport, Conn., agreed. "Unfortunately, people are just very conscious of the appearance of the lawn, and they want to see it spotless all the time," he said, adding that the town spent $85,000 to take residents’ leaves away. Still, he said, Westport encourages leaf composting, especially for some of the 1- to 2-acre properties in the northern part of town. "Residents can blow the leaves into big piles and Mother Nature does the work," he said.

Two years ago, Petronella enlisted a landscaper who mulches leaves and tried it on her own property in Scarsdale, which she described as a "postage stamp." There was leafy residue for a few days after the mowers came through, but it quickly disappeared. "My land is just as attractive as any of my neighbors’ and I didn’t turn on my sprinklers once the past two summers, not once," Petronella said.

The holdouts are not convinced. In Hastings-on-Hudson, Chloe Sikirica, a 50-year-old artist, was blowing leaves off her yard. With twin boys, she worries about the leaf confetti. "If you shred them and leave them, then the kids will track the mulch into the house," she said.

Her one nod to sustainable yard care: leaving leaves around her trees and hedges to provide a natural mulch.

In northern Westchester, Fiona Mitchell of Bedford is a mulching convert. A member of the board of her local library, Mitchell got the idea a few years ago when the library was facing budget cuts. "I said, ‘Hang on, we’re spending all this money on leaves,’" she remembered.

Bedford estimates that 10 workers and 10 vehicles are needed over six weeks to pick up leaf bags and suck up piles of leaves from curbs; unlike other towns, it composts them on site, so it does not pay for hauling.

Now Mitchell does her own leaves, switching the blades on her mower come fall. She said the leaves provide so much benefit to her soil that this fall she "borrowed" some from her neighbor to mulch. And she has become something of a proselytizer for the practice among her neighbors and those in other towns.

"I’m afraid I’m becoming a bit of a mulching police," she said. "My friends call out, ‘I’m mulching, I’m mulching,’ when I walk by their houses."

© 2013 The New York Times Company