Weeds

Weeds' first two seasons proved worthy of their namesake — affably addictive, but nothing too dangerous. Turns out, though, that those were just a tease, a gateway drug leading us to a season 3 that's more potent than anything we'd previously imagined.

Watching Mary-Louise Parker's harried pot-dealing mom, Nancy Botwin, roll her eyes and chew her iced-coffee straw throughout the season-opening deal-gone-bad-gone-worse felt as exhilarating — and well earned — as the rollercoaster plunge that comes after a long, clackety ride to the top. While that intoxicating level of suspense can't possibly sustain throughout the season, subsequent episodes — including a charmingly smarmy Matthew Modine as Nancy's boss at her new ''real job'' — keep up a nice, if occasionally spotty, momentum.

And not to be too moralistic while watching a Showtime series about a drug-dispensing suburban mother, but it's nice to see the often unnervingly naive Nancy face some serious consequences. It was only a matter of time before she found herself at the wrong end of a gun or, worse, applying for legitimate work. Facing both of those possibilities only takes Weeds to a new...um, high — mixing its trademark deadpan humor and heartbreak with the added threat of the genuinely menacing (if still entertainingly droll) U-Turn (Page Kennedy) and his gang. (Good riddance, I say, to Nancy's stifling relationship with Martin Donovan's now-supposedly-dead DEA agent, Peter.)

It's the kind of genre-defying blend that so many ''daring'' shows are trying to pull off now — especially during this Summer of Endless Original Cable Programming. But at its best, Weeds avoids the blatant whiff of desperate envelope-pushing, thanks to an ensemble with dead-on timing and instincts: Kevin Nealon's creative use of facial product, for instance, took the male-genitalia size-off with his mistress' husband from gratuitous to genius. The mistress herself, Elizabeth Perkins, becomes more watchable the boozier and bitchier she gets. And, oh, that Justin Kirk. Playing Nancy's brother-in-law, Andy, he can make anything work, which is why I'm less concerned about his upcoming storyline-jarring Army stint than I should be — though I prefer him at home playing off all of the above.

Most of all, though, Weeds works because of Parker's grounded performance. Whether she's flitting about in search of cell-phone reception while held at gunpoint by gangsters, reacting to Peter's death with one despairing head bob, or unleashing a stripper-worthy ''brick dance'' during an errand for U-Turn on her way to her son's sentencing (for stealing ''Drug Free Zone'' signs, natch), she sells it all as just another day in suburbia. And, now more than ever, I'm buying. A-