Messy genre jumbling has rhyme and reason in Leaves of Grass, as it speaks directly to the film's portrait of life's unpredictability and uncontrollability. Melding stoner comedy, philosophical inquiry, family reconciliation drama, and same-actor-playing-twins cine-stunt, Tim Blake Nelson's film isn't an even-keeled endeavor, prone to lurch at a moment's notice between storytelling veins. That bumpiness correlates directly to the saga of clean-cut Bill Kincaid (Edward Norton), an esteemed classical philosophy professor at Brown who lectures about Socrates's belief in man's need to control himself—and the dangerous illusion of thinking one has succeeded in this regard—and then finds those ideas corroborated once he's duped into returning to his long-abandoned Oklahoma home by identical twin brother Brady (also Norton). Brady is a scruffy pot dealer with enough intellect to have constructed a state-of-the-art hydroponics laboratory but not enough common sense to keep himself safe from a big-shot criminal (Richard Dreyfuss) to whom he is indebted, and Brady's ruse is to use Bill as an airtight alibi for his and cohort Bolger's (Nelson) forthcoming crime.
Leaves of Grass, however, takes its time getting to the action's nitty gritty, content for its first half to just enjoy the natural rapport between Norton's diametrically opposed siblings—as well as that shared by Bill and Janet (Keri Russell), a convenient poetry-adoring English teacher love interest—while also engaging in offhand conversations about self, God, free will, and the dominion one has over his lot in life. Marrying all its disparate elements is a task the film isn't quite up to, and while the resultant narrative and tonal disarray is in tune with its thematic conclusion about finding happiness in embracing a modicum of however-it-goes powerlessness, it still results in somewhat slapdash dramedy that's neither funny nor incisive enough to overcome clunkier elements (such as any scene involving Josh Pais's plot-device orthodontist). Nonetheless, Norton's dual performances are both comedically sharp and engage in a relaxed competing-worldview dialogue that overshadows their inherent gimmickry, the actor's artlessness never finer than during a drunken attempt to woo Russell's beauty that's defined by a halting, awkward naturalism too often lacking from the rest of the genial, scattershot proceedings.