During their 2005 tour with Dylan and Nelson, Buzz McClain of "The Washington Post" believed that The Greencards play traditional American music better than some Americans do, because of their deep respect for bluegrass and the Americana sound. According to David McPherson in "Bluegrass Unlimited" magazine, the band's three-part harmonies evoke the soul sounds of gospel music. Kym Warner has said that Robert Earl Keen, Kelly Willis, and Patty Griffin were key influences musically in The Greencards's sound during their time in Austin, with the previously unreleased Griffin song "What You Are" being covered on their album "Weather and Water". The recordings on "Viridian", in particular the songs "River of Sand", "Waiting on the Night" and "When I Was in Love With You", were said to evoke the sounds of progressive folk rock that emerged in the 1960s. In "Nashville Scene", Edd Hurt noted the eclectic tone of the band's overall body of recordings, and believed that their albums belonged to the tradition of singer-songwriter musicians.