The Vortex, Donmar Warehouse, London; <br></br>Untouchable, Bush, London; <br></br>King Hedley II, Tricycle, London

Sex, drugs and shaky relations (with polite smiles all round)

Sam Mendes has taken his final bow at the Donmar, heading off to embrace the glories of celluloid, so Michael Grandage is now the commander-in-chief. Inevitably, Mendes is a hard act to follow having pulled megastars like Nicole Kidman and been a high calibre director to boot. However, Grandage has recently turned Sheffield's Crucible into a regional powerhouse, attracting top-names including Kenneth Branagh. He has already staged many hits at the Donmar too, as Mendes's smart and charming right-hand man.

Grandage's master plan, as artistic director, is to mix some new angles (more continental plays) with continuities (another Sondheim in 2003). His opening production of The Vortex – Noel Coward's rarely-seen early domestic drama – visually echoes Mendes's final show (Twelfth Night) with its gleaming, mahogany walls. And in general this classy production, featuring Francesca Annis, suggests the Covent Garden crowd needn't worry about a drop in artistic standards.

The Vortex caused a sensation in 1924 and made Coward – then only 25 – the talk of London. It begins as a comedy of manners, but grows increasingly serious. High society is condemned as chronically decadent – albeit with a flicker of hope concerning reform. In Florence Lancaster's drawing room, Pauncefort Quentin and Helen Saville (dapper Bette Bourne and Deborah Findlay) start off bitching wittily about their hostess's "unrestrained" lampshade – "such a bad example for the servants". Annis's Florence then swans in with her much younger extramarital beau, Tom (Mark Umbers), and gaily orders cocktails while preening herself in the mirror.

Any superficial niceties go to the wall after the arrival of Florence's son, Nicky (Chiwetel Ejiofor). To his jealous mother's displeasure, he has a fiancée called Bunty (Indira Varma) in tow and the latter has a long-standing attachment to Tom. Moreover, one of the party is a desperate, closet heroin addict.

It must be said, the drug exposé was probably more shocking in its time and Coward's dramatic climax, with a mother-son showdown in Florence's bedroom, feels a tad forced. Nevertheless, The Vortex is still a startlingly assured near-tragedy that evokes both Hamlet and Ghosts as Nicky cries out at the rotten state of their lives. In fact, maybe the most striking succession is not Grandage's but Annis's recent sequence of roles – playing Gertrude to Ralph Fiennes's Oedipal Prince of Denmark and then Ibsen's stricken matriarch, Mrs Alving.

As the ageing belle Florence, she deftly combines charismatic allure with monstrous vanity and suppressed insecurities. Ejiofor needs to make Nicky's emotional confusion more sharply defined, but his explosions of rage are potent. Strong supporting performances include Findlay's Helen – the Jazz Age equivalent of a morality play's good angel – uttering hard truths with a mix of concern and ruthlessness.

Grandage also shifts Coward towards the 21st century, underlining the contemporary relevance of the characters' obsession with youth, drugs and the self. Though Christopher Oram's sets are essentially in period, with Art Deco dressing tables and Bakelite phones, the cast reflect today's multiracial London. This can, however, feel like an uncomfortable halfway house, as semi-posh accents waver and grate against extremely arch exchanges. One might also wonder what point, if any, is being made by the drug addict being played by a black British actor. Is this meant to be colour-blind casting or is there a trace of racial stereotyping? Whatever the reasons, it's noticeable that Howard Davies' more relaxed, recent production of Private Lives – with Alan Rickman – felt more persuasively fresh and modern.

Untouchable by Simon Burt – aged 27 – probably won't be enjoying a major Donmar revival 70-odd years from now. A modest two-hander set in a bedsit, this isn't a debut that takes your breath away. Two teenage friends, Louise and Manisha, start excitedly glugging booze to celebrate renting their first tiny flat "up Wakey" – over a throbbing night-club in central Wakefield. Domestic harmony isn't destined to last, especially when there's only the one single mattress, when Lou is an easy lay with no goals beyond painting the town red, and when Manni – with stricter Asian parents – has been far more sheltered and should be studying for college. Though nobody mentions narcotics, alcoholism rears its ugly head.

The plot developments are rather predictable but the Bush has rightly nurtured Burt for he has an ear for the lively dialect of West Yorkshire, humour and sympathy, and he slips in multicultural issues unobtrusively.

Actually, I can see this play becoming an instant Fringe favourite with budding actresses on a shoestring budget. Directed by Natasha Betteridge, young Samantha Robinson and Pooja Shah are admirably assured, shifting from ebullience to stroppy misery to mature determination.

Race seems a more divisive issue in King Hedley II, being bound up with the poverty trap and cycles of crime. This is the latest play by the veteran Pulitzer-winner August Wilson to be premiered at the Tric. Set in the 1980s in Pittsburgh's poor black Hill District (where Wilson was born), two grey clapboard houses stand in a junk-strewn yard. Through a narrow chink you see gleaming skyscrapers way uptown (design by Niki Turner), emphasising the economic gulf.

There's a great sense of local community, devotion and resilient humour on this bleak patch of dirt. Playing Miss Ruby – a one-time singer and long-suffering single mother – Pat Bowie manages to be wryly sassy and girlishly joyful about the return of Joseph Marcell's Elmore, who's her old flame and a shabby but loveable hustler. Eddie Nestor's swaggering Mister is a small-time crook with a hopelessly generous streak, and everyone tolerates the cranky, doom-preaching neighbour, Stool Pigeon (stringy Stefan Kalipha).

Still, against the women's instincts, the men are playing dangerous games to beat the system and Ruby's bitter, violent son – Nicholas Monu's King Hedley – could go over the edge.

This isn't Wilson's greatest play. It's slow-moving and too obvious in it symbols – not least with Monu planting seeds then furiously stamping the green shoots of hope into the mud. Nonetheless, these characters' tough lives make the playwright's philosophical questions about self-determination vs a cruel or merely chaotic universe seem startlingly poignant. And though Monu is a little stiff initially, Paulette Randall's company prove one of the most winning, heart-warming ensembles of the year.

k.bassett@independent.co.uk

'The Vortex': Donmar, London WC2 (020 7369 1732), to 15 Feb; 'Untouchable': Bush, London W12 (020 7610 4224), to Sat; 'King Hedley II': Tricycle, London NW6 (020 7328 1000), to 8 Feb