Bluegrass music echoes from honky tonks of ... New York?

If it hadn’t been for “Sheriff Uncle Bob,” I never would have taken my banjo out of the case. Four months ago, I was a novice player in New York City. I assumed I wasn’t good enough to play with other people. But with time off before graduate school, I decided to take a chance.

I walked into a nightclub in Manhattan that was staging a bluegrass jam – and froze. The musicians played at fiber-optic speeds. Their fingers flashed across the strings. What was I thinking?

Then a lanky man in a cowboy hat walked over. “That your instrument?” he asked. He looked fresh off the set of a low-budget Western. His black vest was adorned with a silver star and embroidered with the words “sheriff of good times.”

“It’s mine,” I said tentatively.

“Well,” he said, “why aren’t you playing?”

This was my first pep talk from the man affectionately known as Sheriff Uncle Bob, the grandfather of New York’s bluegrass jam scene. By the end of the evening, I had unsheathed my banjo – and played in public for the first time. “You can find any kind of good live music in New York,” the sheriff told me. “But in bluegrass, the jam is a tradition. You don’t come here for the quality of the music but for the spirit.”

Many people find the existence of a thriving bluegrass scene in New York surprising. Bluegrass is considered mountain music: the antithesis of hyperactive urban life. Yet not only is the music an urban phenomenon, but the inclusiveness and diversity of the bluegrass community in New York is among the most vibrant and unique in the country.

“The acoustic purity of bluegrass makes it a marker for Southern authenticity,” says Jonathan King, an ethnomusicologist and PhD candidate at Columbia University. “But it’s more contrived than people give it credit for.”

Bill Monroe, the father of bluegrass, fused old-time music, Irish influences, jazz, and blues to create a new sound in the 1930s. Through his use of emerging radio technology, bluegrass became popular in Atlanta, Chicago, and cities in North Carolina. As more Americans migrated to urban areas, they latched onto bluegrass as symbol of authentic America – the “real” thing – including in New York, where it flourished during the folk revival of the 1950s and ’60s.

Mr. King believes bluegrass fits well here. An intense drive and speed characterizes the three-finger banjo style that Earl Scruggs, in particular, developed in the 1940s. “It’s perfect for people who ride the subway all day,” King says.

Still, New York isn’t Nashville, Tenn. The city hasn’t supported a country music station since the 1980s and features only one bluegrass radio program, which broadcasts from Columbia University.

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The bluegrass culture that does thrive here owes at least some of its vibrancy to Robert Saidenberg, known to musicians as simply the “Sheriff.” Mr. Saidenberg has lived in the West Village for nearly 70 years. He used to work as a filmmaker and played folk music on the side. In 1991, he bought a steel guitar and went to West Virginia to study with the master of the instrument, Jerry Douglass. Saidenberg was hooked.

“Bluegrass was such a communal thing,” he says, remembering his early attraction to the music. “You could always find people in a parking lot and play.”

Back in New York, he joined a band and developed his musical persona as the “sheriff of good times.” In 1996, he cofounded a weekly jam in the West Village. Currently, the jam takes place at The Grisly Pear bar on MacDougal Street. Each Wednesday night, the energetic sound of fiddles, mandolins, and banjos fill the dark rooms. Booths and tables overflow. Tourists wander in, surprised by music they never expected to find in the Big Apple.

Bluegrass does foster a social environment atypical to Manhattan. Emily Day, a young clinical psychologist, first heard live bluegrass music at the Sheriff’s jam last spring. “I felt like I’d struck gold,” she says. “You just don’t walk into most places in New York and join in. It’s what people in my generation are craving: social events that are worthwhile in themselves, which drinking is not.”

Ms. Day took up banjo. Aside from the Sheriff’s jam, she often plays at Sunny’s, an old sailor’s bar on the Brooklyn waterfront. Sunny’s has a vaulted wooden roof and lace curtains. On Day’s first trip there, the other musicians offered her homemade strawberry shortcake. “I felt like I was down on the Delta somewhere,” she says, “or on someone’s back porch.”

Day likes the lack of pretension of New York’s bluegrass community. A construction supervisor with a mandolin will play with an architect on banjo and a classical violinist. “There’s a universality to the music,” Day says. “How exclusive can you be when you’re singing, ‘You Don’t Have to Be a Baby to Cry?’ ”

Noam Pikelny likes the openness of the culture here, too. Considered one of the best banjo players of his generation, Mr. Pikelny recently relocated to the city after having lived in Colorado and Nashville. “It was mind boggling,” he recalls of his first encounter with the Sheriff’s jam. “There’s nothing like that in Nashville. All the great jams there happen behind closed doors.”

Anyone here can pick up a fiddle and play with someone else. Multiple jams and concerts are held every night in Manhattan and Brooklyn. A website, nycbluegrass.com, and an electronic mailing list, Ponkiesburg Pickin’, track the weekly events.

While Pikelny misses the professional music scene in Nashville, he likes New York’s egalitarianism. For example, old-time musicians (those who play more traditional mountain folk music) and bluegrass musicians have a historic rivalry. In Nashville, a claw hammer banjo player (who frails the strings instead of picking them) would never join in a bluegrass jam. Nor would bluegrass and old-time jams happen at the same venue. But both sounds meld at the Grisly Pear on Wednesday nights.

“Nobody is here to criticize,” the Sheriff says. “This is a party, not a rehearsal.”

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The sheriff’s jam can still intimidate newcomers – even a professional violinist like Melissa Tong, who plays in a number of orchestras. Bluegrass jams center around improvised solos, called “breaks,” that take place between song verses. Improvisation was Ms. Tong’s greatest fear. In her professional life, she only performs pieces she has memorized note-for-note.

After months of watching in the audience and assurances from the Sheriff, Tong finally jumped in. She found the experience liberating. “Improvisation makes you connect to your instrument in an intimate way,” she says.

“When you’re classically trained, your brain says, ‘you must execute this phrase in this way.’ When you improvise, you’re in the moment.”

Bluegrass has become Tong’s release from the rigidity and pressure of the classical world and from her daily life in New York. “Bluegrass connects people in the middle of this crazy life to something simpler – a time when people had the luxury of sitting around pickin’ all night,” she says. “We like to feel like we can still do that, even with 70-hour work weeks and cabs and trains and lease problems.”

Unlike Tong, I had little musical training to rely upon when the Sheriff finally convinced me to play. I struggled with the speed. But the other banjo players helped me with chord changes and offered tips.

Like the Sheriff, I was hooked. In just a few months, I was taking my first “breaks” – and belting out songs about the Blue Ridge Mountains.