In short, jamgrass is a freer and more expansive version of traditional bluegrass. But it helps to view it in terms of how all music, like language itself, evolves.
Music is a language. And as language evolves, so too does music.
Some would say the sensory and atonality of of Debussy (said to be influenced by a literary style in France in the late 19th century known as Symbolism) somehow was the progenitor to American-born jazz. And jazz, known for its improvisational jams, could well be what evolved traditional bluegrass music to jamgrass sometime in the latter half of the 20th century.
Really? The jamgrass of the David Grisman Quintet, Peter Rowan & Tony Rice, the Yonder Mountain String Band, and, arguably, Phish derive from the composer of Preludes, En blanc et noir, Etudes and Nocturnes for Orchestra? Note that Debussy was born in 1862.
Indeed, the DNA of jamgrass might well include French origins, but also be heavily influenced by the polyglot culture of New Orleans (itself a product of Voodoo rituals, soulful gospel, barroom brass bands, and people named Buddy Bolden and Nick LaRocca). Just the same as how bluegrass – with its long traditional reaching back to Appalachian genres, once described as “Scottish bagpipes and ole-time fiddlin’…it’s Methodist and holiness and Baptist,” with roots in migrations from Ireland, Scotland, and England going back to the 1600s – evolved into jamgrass, borrowing the jams of improvisational jazz.
To say it’s all a melting pot is an understatement.
Jamgrass is similar to bluegrass, but with a few more instruments, a more open-to-interpretation format, and, a lot of fans who want for something more. What distinguishes jamgrass from bluegrass is that it pulls from rock and pop, it has some pretty hopped up progressions, it often has additional instruments (drums, electric guitars, and the “resophonic” slide dobro guitars), and don’t expect one performance to be the same as any other. Jamming is all very in-the-moment.
One commenter on Reddit, Banjoman74, put it this way:
“…there is a complicated interaction [with jamgrass] constantly taking place where they have to pay close attention to one another, because, as a musician, they aren’t 100 percent certain where the lead is going. They have to respond and react. Yes, sometimes there are failures. But sometimes there are spectacular moments captured where everyone on stage reacts to this magical moment. It’s exciting and dynamic and everyone on stage is a little more on edge. And that makes them much more attentive to each other and keeps the music alive, even though they may have played the song 100s of times before.”
Banjoman goes on to say that there is such a thing as bad jamgrass, something that happens when the band members don’t pay close enough attention to the lead and consequently fail to react in a cohesive way. He says the skillset for jamgrass players is different from players of a traditional bluegrass band.
We assume jamgrass fiddlers are different from the violinists working their way through a Debussy composition.
But bluegrass music and jamgrass music is different enough, in the end, that the individual seeking a bluegrass band for hire should do their due diligence to ensure that a looser, less traditional jamgrass band doesn’t show up for the gig.
The word “jam,” it should be noted, has undergone its own metamorphosis as well. Once strictly used to refer to improvisational passages in jazz, it now more broadly means “that thing I do or like.” Which is so fitting for jamgrass – it’s a thing that constantly evolves, that keeps musicians and audiences alike on their toes, yet something that keeps fans altogether on their feet, swaying and dancing to something visceral and unpredictable and yet has a certain timelessness.