Where is Mary the afternoon her husband goes missing in the novel, Afterward?

The gardens of Lyng are where Mary spends her afternoon the day her husband goes missing. She walks about them, coming up with ideas for how to change them and make them more aesthetically pleasing. The gardens also represent Mary's inexplicable sense of security the day following her knowledge of the Elwell suit, and Mary's afternoon in the gardens is one punctuated by mundane concerns and domestic affairs rather than the more existential worries she had been facing the day before. It is in the gardens, however, that Mary is approached by the strange man, and this interaction is the first instance where Mary's pleasant afternoon begins to derail as she learns soon after that Ned has gone missing.