Bluegrass is having a moment. Billy Strings is selling out arenas, Molly Tuttle is on late night TV, and a lot of curious new listeners are walking into their first jam with no idea what people mean by "mash" or "dog music." The good news: almost every branch of bluegrass traces back to one person's band, so the tangle of subgenres is really a family tree. Follow the line and it makes sense.
Below, the genre is laid out the way Marcel tells it, era by era. Each branch names its key artists, and every one is a link to a full "where do I start" Onramp guide. Pick any name and dive in.
A note, borrowed from Marcel: subgenres do not die when the next one arrives. This is a map of each style's heyday, not its funeral. People still play all of it, everywhere, today.
The Monroe Family
Brothers Bill, Charlie, and Birch Monroe played radio across the Midwest and South in the 1930s. After the Monroe Brothers split in 1938, Bill formed the Blue Grass Boys and joined the Grand Ole Opry a year later. When he hired banjoist Earl Scruggs into the 1945 lineup, alongside Lester Flatt, Chubby Wise, and Cedric Rainwater, the sound crystallized. That band is the birth of bluegrass as a genre, the one it is literally named after.
Traditional Bluegrass
The playstyle of the first two generations, before the folk revival. This is the standard repertoire that lets total strangers sit down and jam together anywhere in the world. Nearly everyone here passed through Bill Monroe's band at some point, then struck out on their own. If you have seen O Brother, Where Art Thou?, you already know Ralph Stanley's voice.
The Folk Revival
Folk artists like Pete Seeger and Woody Guthrie worked hard to expose their fans to traditional genres, and bluegrass rode that wave onto college campuses and the new multi-day festival circuit. The big change: the bluegrass cover became routine, and for the first time bands from outside the South, like California's Kentucky Colonels, gained real notoriety. Clarence White's guitar here would shape every generation that followed.
New Grass Revival
In 1971, members of the folk-revival band Bluegrass Alliance left to form New Grass Revival, led by Sam Bush, whose mandolin chop pulled rock and world music into bluegrass. The first wave gave us pop, rock, and funk-infused bluegrass; the second lineup, adding a young Bela Fleck, leaned into odd time signatures, Irish influence, and pure instrumental virtuosity, and even charted on country radio. The era closes when the band breaks up in 1989.
David Grisman & "Dawg Music"
In 1975 David Grisman formed a quintet and invented what he called "dawg music," a wild new-acoustic mix of bluegrass and 1930s gypsy jazz. It featured Tony Rice on guitar, who had already made one of the most influential bluegrass records ever and then drove across the country to make one of the most influential new-acoustic ones. Grisman became a proving ground the way Monroe and Bush were: his alumni went off to define the style, with Tony Rice coining "spacegrass" for his own unit.
The Bluegrass Album Band & "Mash"
In 1981 Tony Rice cut a record with JD Crowe, Doyle Lawson, Bobby Hicks, and Todd Phillips. It felt more like a band than a solo album, so they shared equal billing and titled it simply The Bluegrass Album. It blew up, and the touring name stuck: the Bluegrass Album Band. This is the genesis of neo-traditionalism, casually called "mash": capo the fourth fret, kick the banjo off at 160 bpm, and, for the first time, let the guitar take real lead solos.
Jamgrass
Jerry Garcia had been playing bluegrass on the side for years, with Grisman and in Old & in the Way, so when jam-band culture met bluegrass, this was bound to happen. The legendary "Pizza Tapes," Garcia, Grisman, and Rice picking together, are the perfect artifact of it. Out in Colorado a group of friends formed String Cheese Incident, and the scene exploded: rock elements, big light shows, and a focus on long instrumental solos. Best experienced live.
Progressive Bluegrass
The kids who grew up on newgrass put their own spin on it: crossover appeal, densely arranged material, and pushing the instruments to do things they were never designed to do. Nickel Creek, formed by children in 1989, got their big break in 2000 with a self-titled album produced by Alison Krauss that had huge pop reach while keeping serious instrumental showcases. Lately the style has moved away from crossover and deeper into ambitious, sometimes obtuse arranging.
Alternative Grass
Around the time O Brother briefly pulled folk back into the mainstream, another sound appeared that cared less about holding onto tradition and more about attitude and presentation. Old Crow Medicine Show earned a rare standing-ovation encore for a new act at the Opry in 2001. Much of the rest has more in common with the punk scene than the jam, sometimes called folk-punk or punk-grass.
Modern Bluegrass
This is a fusion-heavy era. Billy Strings combines neo-traditional mash with jamgrass; Molly Tuttle turns toward traditionalism with a newgrass flair; Sierra Hull pushes progressive bluegrass to new heights. If you are just arriving, follow these modern acts, then dig back into the legacy artists above, and go to a festival.
Start listening
Every artist on this tree now has a full Onramp guide, from Bill Monroe to Billy Strings and every branch in between. Pick any name above, or wander the whole catalog.