First things first: While jamgrass certainly is progressive bluegrass (a form of it, at least), not all progressive bluegrass is jamgrass. More than a few music critics, and even fairly serious fans, tend to use the tags interchangeably, but there exist key differences in their attitudes toward experimentation. Even at their most outré, progressive bluegrass’ core outfits—Nickel Creek are a prime example—still retain a string-band flavor that, however faint, reaches back to the genre’s more traditional iterations. This isn’t the case with jamgrass acts, who, in addition to pouring their improvisational chops into extended workouts, think nothing of cutting their ’grass with funk grooves, bouncy ska, swinging jazz, Indian microtonality—even polka accordions!
This certainly is the case with The String Cheese Incident’s latest full-length, Believe. In keeping with the band’s mischievously anarchic spirit, the music hops across Irish-kissed folk rock, porno disco, reggae, and riff-crunching power pop. Half the time they don’t even remotely resemble front-porch pickers and grinners. Jamgrass’ other key outfits are equally audacious: Where Railroad Earth can follow up a down-home mountain ballad with Phish-style funk, Greensky Bluegrass have been known to insert Bruce Springsteen and even Michael Jackson covers into their live shows. Leftover Salmon are so maddeningly eclectic, they’ve come up with their own genre tag: polyethnic Cajun slamgrass.
Obviously, the neo-hippie jam band movement—Phish, Col. Bruce Hampton and The Aquarium Rescue Unit, Blues Traveler, Widespread Panic, et al.—looms large over jamgrass. But a more direct lineage leads back to the highly influential Béla Fleck and the Flecktones, who, in the ’90s, used bluegrass instrumentation to create what essentially is acoustic-based jazz fusion and world music. Fleck, in turn, built his sound upon innovations made by bluegrass-based groups orbiting around the Grateful Dead in the ’70s and ’80s—Old & In the Way and the clutch of other collaborative albums released by Jerry Garcia and mandolinist David Grisman are notable for sure. But it’s the latter’s other project, The David Grisman Quintet, who are the most vital. The blend of virtuoso picking, hot jazz, and folk music documented on their 1977 self-titled debut is the tree that would go on to seed all future jamgrass.