You're probably wondering what flowers have to do with Almost Famous. This movie is about rock stars, not gardeners, right? Well, as it happens, roses are a subtle yet significant visual motif in the film, appearing prominently three times.
The first appearance of a rose pays homage to the cover of rock god Neil Young's 1973 live album Time Fades Away. The album art is a photograph from one of Young's 1973 arena concerts, taken from the perspective of the performers looking out at the audience. On the stage floor, in front of the camera, is a single red rose. This image is almost perfectly replicated in Almost Famous when Stillwater takes the stage for the first time.
The morning after Russell's "real"-seeking, LSD-filled, I-am-a-golden-god-shouting night in Topeka, the rose appears again. Right before he rejoins his less-than-ecstatic band on the bus, a loopy Russell picks a rose from a bush outside the house. "I hurt the flower," he mumbles, as Dick prods him along. While this moment seems unimportant at the time, as if it's just a random action by a still pretty tweaked out Russell, it makes more sense in light of the appearance of the final rose.
After the new manager Dennis Hope gives his spiel to Stillwater in Cleveland, Crowe overlays a bit of dialogue from Lester Bangs: "You're coming along at a very dangerous time for rock and roll," Lester explains, referring to Hope's big-business mentality. "The war is over, they won," he concedes. "They will ruin rock and roll, and strangle everything we love about it." Cat Stevens's "The Wind" begins to play, and we cut to Penny dancing by herself in the empty, trash-filled Cleveland auditorium, holding—you guessed it—a rose. The extended scene from the director's cut lingers on Penny even longer.
William and Penny, as the old saying goes, see the world through rose-colored glasses. They both bring a certain purity to rock and roll, which, as Lester points out, is rapidly becoming tainted. The rose is connected to William in his innocence and idealism, to Penny in her heart and beauty, and to both of them in their unadulterated love of rock and roll.
Meanwhile, we watch Russell and the rest of the band lose touch with this love as they wrestle with the challenges of stardom. Russell does indeed "hurt the flower," Penny, whose fragile beauty is captured in her dance in Cleveland. The rose embodies the purity of rock and roll at its best, and it symbolizes those who truly do it for love of the music.