There is no question that you feel you are watching a great play as Carson McCullers’ The Member of the Wedding unravels, rather slowly, on the wide acres of the Young Vic stage. The problem with Matthew Dunster’s unevenly acted and overly leisurely production is that it’s not always easy to follow exactly what is going on, or what exactly is being said.

Basically, the play is a study in the adolescence of a 12-year-old tomboyish American girl, Frankie Addams, in a Southern back yard and kitchen in the summer of 1945. The war seems a long way away, and is coming to an end. Frankie’s older brother is getting married and Frankie wants to be a “member” of his wedding party; she’s too young.

This disappointment is the flash point of her mounting frustration and sense of alienation. Frankie’s mother is long dead and her father is an irritable fusspot. Her friends are starting to go out with boys.

Her only refuge is the kitchen and the wise counselling of the family cook, Berenice Sadie Brown, whose own family troubles indicate a seething unrest in the black community outside. She also has a little seven-year-old cousin, John Henry West, who’s a willing accomplice in her fantasies and play acting in the arbour.

Adapted by Carson McCullers from her own novel, the play has an unusual richness but seems remote from our experience. Frankie’s sustained adolescent strop presents an enormous challenge to a young actress (Julie Harris made her name in the role on Broadway in 1950) that newcomer Flora Spencer-Longhurst, a graduate of the National Youth Music Theatre, doesn’t quite meet. She gets the dirty elbows and dirty feet of the role but shades monotonously into shrieking when vexed.

The play is powered by the single-named American actress Portia as Berenice, who conveys a wealth of experience and gravity in her ministrations and soul chanting. There’s a nice cameo from Alibe Parsons as the itinerant vegetable lady, and Berenice’s own world erupts on the white man’s porch when her volatile son Honey Camden Brown (John Macmillan) calls by like a whirling dervish.

The series of tragic revelations belong more to the page than the stage in their execution. And the climactic thunder storm seems more of a device than an inevitable disruption of the wedding party. The production suffers, too, from a too long first half (the first two acts) being brutally wrapped up in the short third act. Robert Innes Scott’s huge design is set on an unsettling angle to the audience, resulting in an intermittent lack of focus.

- Michael Coveney