BRNO, Czech Republic - Robert Krestan, singer, songwriter and frontman for the Czech bluegrass group Druha Trava, is a brooding stage presence. A solid figure with shadowed eyes and a wild shock of long gray hair, he dwarfs the mandolin he cradles against his chest, singing with a gritty passion that a fan at a recent concert explained was a "real Czech growl."
Druha Trava means "Second Grass." It is at the forefront of the flourishing Czech bluegrass scene, but as its name implies, it reaches far beyond the classic bluegrass genre for inspiration.
Formed in 1991 by Mr. Krestan, the banjo player Lubos Malina and other veterans of the acoustic music scene that had long thrived in Czechoslovakia, Druha Trava can delight hard-core fans with scorching versions of bluegrass standards.
For the most part, however, it uses American roots music as a launching pad for its own synthesis of jazz, pop, folk and even classical motifs. In doing so it transforms a quintessential American idiom into a richly textured, highly personal statement that defies genre classification.
Call it Central European bluegrass rock, perhaps, or Czechgrass.
Over the years the distinctive sound and the band's virtuoso musicianship have won Druha Trava multiple Czech music awards, as well as a loyal following at home and in the United States, where the group tours at least once a year. Its next American tour begins Sept. 20.
"We grew up on simple music, bluegrass music, simple old country music, acoustic country music," Mr. Krestan said between concerts during the group's current summer tour through the Czech Republic and other countries. "It was the music of our youth, of our heart."
But with sensibilities also honed by rock 'n' roll, world music, their own Czech heritage and other influences, he said, "bluegrass music wasn't enough for us."
The band couldn't "squash" everything they wanted to convey into the tight format of traditional bluegrass, he said. Instead, they chose to use bluegrass instruments to play whatever sort of music fitted their taste.
Mr. Krestan's raw vocals and original songs are an important part of the mix.
Though he often sings cover songs in the original English, he is best known among Czech fans for his own elliptical, at times provocative, lyrics, which are somewhat reminiscent of early Bob Dylan. "It's nothing but a mean Sunday morning, my virginal drummer," a song, "El Santo Día," begins.
Before the collapse of the Communist government in the Velvet Revolution of 1989, playing American-style folk music was an oblique means of protest against the regime. Like Dylan's songs, some of Mr. Krestan's writing achieved the status of counterculture anthems.
"The fact that Robert writes his own music with his own lyrics is the main thing that makes us different," Mr. Malina said. "Everything else is around the songs."
Along with Mr. Krestan and Mr. Malina - who plays other instruments in addition to the banjo - the band's current lineup includes Lubos Novotny on dobro, Petr Sury on acoustic bass and Emil Formanek on guitar.
Joining them for several stops on the summer tour was the American folk and bluegrass singer-guitarist Peter Rowan, who brought his own songs and improvisations to the blend.
Mr. Rowan has collaborated on and off with Druha Trava for a decade, but until this tour he had not played live with the group since just after they put out a joint album, "New Freedom Bell," in 1999. On this trip he also worked in the studio on a song for a new solo album that Mr. Malina will release this summer.
"There's always been this exchange with them," Mr. Rowan said. "For me, that's a real interest. If I were just here playing bluegrass, it wouldn't be so interesting. But because it's all about original material, that keeps me sparked."
One of Druha Trava's most compelling songs is a powerful meld of American and Czech sensibilities that Mr. Rowan and Mr. Krestan wrote for the "New Freedom Bell" album.
Called "Kridla" ("Wings"), it begins with a lovely, lilting melody composed by Mr. Rowan. Mr. Krestan, his voice dark and sweet, then joins in with a second, more somber tune, singing poetic lyrics that evoke images of yearning, loss and surrender.
Mr. Krestan said writing that song was a memorable experience, as his input and Mr. Rowan's came together and bridged temperament and traditions.
"When we were writing that song, I felt inside me some kind of magic, for the first and last time of my life," he recalled. "I felt it through that melody, through Peter's guitar; it came into my chest and into my brain.
"This connection and this feeling are very rare. It was magic."