Colorado-Based Yonder Mountain String Band's Grass Is Not Blue

05/26/2015 04:52 pm ET | Updated May 26, 2016

Colorado-based Yonder Mountain String Band doesn't want to be associated with grass -- blue, new or probably any other.

Trouble is the group's musical stylings are hard to define. In a recent Rolling Stone piece about the evolving sound of bluegrass, Yonder's name came up several times: "A truly American artform, bluegrass music today encompasses everything from the jamgrass of Yonder Mountain String Band to the traditional sound of Del McCoury to the more eclectic flavor of Trampled by Turtles."

iTunes labels Yonder as "country," but Sirius XM rarely airs them on its traditional bluegrass channel, instead choosing to play the band on its Jam ON channel.

Founding member Adam Aijala, whose guitar playing forms a framework for many of Yonder's songs, and violinist Allie Kral, sat down with me Saturday night before performing their debut, headlining set at the seventh annual Rooster Walk Music and Arts Festival in Axton, Virginia.

"You're not going to know we don't play traditional bluegrass," Aijala says. "When they hear our name, people think of overalls and hay bales.

"We weren't intentionally trying to do something different. I didn't know any bluegrass until I was in my 20s. When I met all the guys it was a new thing. We're all rock influenced so it doesn't sound like bluegrass. But we got more comfortable."

And while Yonder has been redefining bluegrass music for nearly two decades, this past year has been redefining for Yonder. The departure of founding member mandolin player Jeff Austin opened the door for Kral, formerly of Cornmeal, to join Yonder along with mandolin virtuoso Jake Joliff.

Aijala says the addition of Kral and Joliff have infused a new vibe into the group's music. "It's been 17 years (since Yonder started), but it feels totally new," he says of the group's new album, "Black Sheep," which will be released at the Telluride Bluegrass Festival in June. "In the past year, we've gotten even more comfortable with Allie and Jake."

It's also been Yonder's best year, at least for Aijala. "It just feels like we've been re-energized," he said.

"To me it feels just totally new. You spend so much time together as a group and crew and Allie and Jake are new. It's a super friendly, gung-ho attitude in a good way. I look forward to playing shows now."

And what's old is new again when it comes to the new album. "It's not overproduced, this is all acoustic," Aijala says. "The songs are evolved. The lyric content I think it's different. It's more like some of our early records. It has a lot of bluegrass rhythms, but nothing traditional bluegrass. I like the album a lot."

"It sounds very Yonder," Kral added.