Reviewing the world premiere, Mark Swed of the Los Angeles Times described Flower Power as a "a rock ‘n’ roll-ish concerto." He wrote, "The rocking comes in complicated, intricate ways that require as much attending to as, say, Miles Davis' concerts at the Fillmore did. When Mark Stewart's bluesy electric guitar wails, the hint is of the creamy textures of Cream. Ken Thomson on his clarinets might be Charles Lloyd loving-in. [...] Climaxes build and fade, build bigger and fade, joyous but with an edge."[2] Falling James of LA Weekly also praised the work, saying that it "evokes the '60s spirit of rebellion and change without relying on the usual musical clichés associated with the decade."[3]
Reviewing the U.K. premiere performance by the Bang on a Can All Stars and the RTÉ Concert Orchestra conducted by Ilan Volkov, Adrian Smith of The Journal of Music remarked, "While the playing of the ensemble had a wonderful quasi-improvisational freedom, the piece somehow managed to maintain a forceful sense of direction and the tension never wavered."[4]