It would be easy to talk about the infectious joy of the Poncho Sanchez Latin Jazz Band at the Carter-Barron Amphitheatre last night. How they filled the arena with rhythm and delectable horn charts; how by the time they invited the audience to get up and dance, dozens of people had already started; how they chewed on zesty pieces by Herbie Hancock, Horace Silver, and Willie Bobo, and plain and simple rocked the house.

But let’s talk instead about their opening act, Edmar Castañeda.

Castañeda, a 32-year-old from Bogota, is so different for the DC Jazz Festival that it’s easier to start off with what’s not different about him. To wit: He plays improvised jazz. It’s just that he plays it on a harp. And plays jazz that’s rooted deeply in the many folk-musical traditions of his native Colombia. Neither of these is completely new; there have been a few harpists in jazz, Dorothy Ashby and Alice Coltrane most prominent, and Charles Mingus experimented with Colombian music on his late-period work Cumbia and Jazz Fusion. But Castañeda marries these two out-there concepts, presenting them in an unconventional trio featuring soprano saxophonist Shlomi Cohen and percussionist/drummer Dave Sillerman (whose zoo of odd cymbals, chimes, and bells ensure that he’s a percussionist first, drummer second). The music is unique and very beautiful, but without doubt a bold step for the festival to take.

Nevertheless it paid off. Castañeda is a serious virtuoso on his instrument, threading remarkable runs of melody and chords with his right hand while his left kept a thumping foundation that sounded for all the world like an electric bass. He also had a facility for holding down the Colombian rhythms on “Cuarto de Colores” and “Entre Cuerdas,” explaining to the audience that these were based on the llanera and Joropo styles of the Colombian and Venezuelan plains. The harmonies were very close (chromatic, even), which made them rich and gorgeous, although when Castañeda took a solo turn on “Jesus de Nazareth” the sound veered decidedly new age. The direction changed, however, when Castañeda introduced his beautiful (and newly pregnant) wife, vocalist Andrea Tierra, to join the trio for the concluding “Carrao, Carrao” and the Colombia-celebrating “Canto.” Hers was a deep, soulful voice, one that could obscure the sonorities of her husband’s harp, but the sound they made together was too wonderful to complain much.

“Prepare to be amazed,” WJLA’s Leon Harris had warned us before the set —- and we were. The DCJF’s ability to pack in brilliant surprises like Edmar Castañeda is a primary reason why it’s welcomed back every year.