The American scenes are filmed in and around Dunedin in New Zealand where traffic drives on the left-hand side of the road and the vehicles are all right-hand drives. In the scene after Ted Hughes has admitted his first infidelity, Sylvia Plath walks out into the rain and gets into the car which is clearly American and has a left-hand drive. But the other vehicles in front, seen in silhouette, while all seeming American, are all right hand drives.
When Ted Hughes and Sylvia Plath are in bed together and she is discussing her suicide attempt, you can clearly see Daniel Craig's tattoo through the make up on his shoulder and 'Gwyneth Paltrow (I)''s hair net to which her wig is attached.
The film begins with the time that Sylvia Plath and Ted Hughes met, and the trees are shown in autumn colors with falling leaves. However, Sylvia and Ted met in late winter, February of 1956, when the trees would have been bare.