Little Shop of Horrors, West Yorkshire Playhouse, Leeds <br></br>Secret Heart, Royal Exchange, Manchester <br></br>The Adventures of Huckleberry Finn, Tobacco Factory, Bristol

Flower power makes a comeback

Who ever said it was grim up North? In West Yorkshire Playhouse's terrific production of Little Shop of Horrors, it's skid row in urban America that looks as bleak as hell. A huge iron bridge looms menacingly over the stage, against a night sky. The thunder of passing trains is accompanied by spitting flashes of electricity. They, in turn, illuminate the alley below: a litter-strewn terrace of dilapidated shops.

Then the mood distinctly changes as Howard Ashman and Alan Menken's mock-horror musical – written in the Eighties but based on Roger Corman's 1960s spoof B-movie – starts making you smile. By way of a prologue, three sexy ladies in bright pink cocktail dresses sing the catchy title number, doo-wop style. They shimmy down the street looking more like The Ronettes than ill-boding Fates. Next, the dusty frontage of Mushnik's flower shop swings open and we meet the comical smalltimers who are about to become famous for a botanical freak.

Mr Mushnik's geeky assistant, Seymour (Jeremy Finch), not only desperately fancies the cashier, Audrey (Josie Walker). He's also nurturing a "strange and interesting plant". Of course, this sci-fi bud – which he calls Audrey II but which looks like a grinning snake's head lurking in an artichoke – will soon take over everybody's lives. For it starts pulling crowds and making headlines. More scarily, it grows at a monstrous rate, starts talking and demands – when no one else can hear – that Seymour satisfies its appetite for human flesh and blood.

This production is highly polished and a blast, proving artistic director Ian Brown is an admirable successor to Jude Kelly. Jonathan Fensom's stage design is impressively grungy, with the grand scale and detailing of a film set. Meanwhile, director Christopher Luscombe's cast manage to play caricatured types with endearing warmth and brio. Several of them are storming singers too. Walker's Audrey is remarkably touching, waxing lyrical about her dreams of suburbia in "Somewhere That's Green", and Mel Taylor is show-stopping as the gravelly voice of Audrey II, belting out "Suppertime" like a hybrid of Louis Armstrong and Dracula.

Graham Macduff needs to relax and let rip a little more as Orin, Audrey's beastly rockabilly boyfriend whom Seymour wants to kill. Still, he doesn't spoil enjoyment of the splendidly silly twist to Orin's character as he strips off his leather jacket to reveal he's a sadistic dentist.

Menken's score can sound derivative and, generally, the numbers suffer by comparison with The Rocky Horror Show. But innocent, happy harmonies of the Fifties and Sixties are amusingly ironic here, especially as Seymour starts turning into America's answer to Sweeney Todd.

The shifting symbolic meaning of Audrey II is also rich and seriously loaded by the end – at least for adults in the audience. The puppeteer-operated plant – as well as having the appeal of The Muppets and The Munsters rolled into one – looks suspiciously like a sprouting phallus and a paranoid man's nightmare of a vagina dentate. Given time, it seems more like a metaphor for consumerist greed, drug addiction or subconscious murderous urges. And finally, as you glimpse a strip of military camouflage netting at the back of Audrey II's head, you see it's a giant commander's helmet above an all-consuming maw. So Little Shop emerges as a post-Vietnam protest musical with its final chorus, "Don't Feed The Plants", as a pacifist anthem couched in black humour. That certainly merits pause for thought in these hawkish times.

If Seymour is a shy guy with a developing psychotic side, the sensitive adolescent Joe Maloney in Secret Heart transforms into a tiger far more life-enhancingly. It's part of a rite of passage where he makes friends with a girl and wards off the bullies in his fictitious north-eastern home town of Hellmouth. Having had my fill of clowns, I was wary of David Almond's children's story where Joe runs away to the circus and is emboldened to fly on a trapeze with his new-found soulmate, Corinna, before embarking on further woodland adventures. However, Amanda Dalton's adaptation proves a quietly enchanting seasonal show, staged by the young experimental team Wilson&Wilson (director Wils Wilson and designer Louise Ann Wilson).

It's the transitions between the mundane and the magical that are pulled off with courage and delicacy. The first couple of scenes are very Grange Hill as Joe's single mum packs him off to school and he gets picked on by his peers. Yet the set's circular island of broken concrete and verdant grass hints at a fairy ring. Ben McKay's pale, skinny Joe also looks elfin, so you accept his poetic trances when he appears to be in touch with primitive or ethereal spirits.

Hokum can seem perilously close and, elsewhere, the ensemble's circus skills look slightly wobbly. But June Broughton is enthralling as the wizened, blind, wise woman, Nanty Solo, who hobbles up to Joe like a tropical spider in her ragged, black-and-yellow velvet jacket. McKay's shamanistic dance is – against the odds – electrifying, too, as he crawls under a tiger skin and builds up to wild spinning and leaping. This is riveting fare for young and old: gentle and humorous and occasionally fierce.

By contrast, The Adventures of Huckleberry Finn probably won't make anyone tingle with excitement, as adapted by writer-director Dan Danson and composer Malcolm Newton. The social lesson that dawns on Mark Twain's ragged boy-hero is certainly sound, as he drifts down the Mississippi with the runaway black slave Jim and realises he must fight against the racism of his far-from-civil fellow whites. The location is apt, too, considering Bristol's own historic links to the slave trade.

However, in theatrical terms, this is lamentably feeble. Danson's imagination seems to have dried up here. The rough timber set looks enticing at first. But when there's hardly any attempt to make us believe its central jetty has become a raft, one starts longing for lush cinematic riverscapes.

Newton provides a meagre scattering of songs which fall flat, though his use of banjo and fiddle could have been fun. The episodic story seems hopelessly scrappy and most of the acting just ain't good enough – not least Jon Bonner, whose Tom Sawyer appears to have been possessed by the spirit of a stolid bank manager. As Huck, Simon Tcherniak is lovably gangly with contained charisma and vulnerability, while Kirris Rivieré's Jim is a steady gentle giant. Nevertheless, they're pitifully marooned in the middle of this production.

k.bassett@independent.co.uk

'Little Shop Of Horrors': WYP, Leeds (0113 213 7700), to 8 Feb; 'Secret Heart': Royal Exchange, Manchester (0161 833 9833), to Sat; 'Huckleberry Finn': Tobacco Factory, Bristol (0117 902 0344), to Sat