In “The Landlady,” Dahl uses chrysanthemums—a flower representing death—to foreshadow the landlady’s murderous intentions, as seen in the following passage:
Billy caught sight of a printed notice propped up against the glass in one of the upper panes. It said BED AND BREAKFAST. There was a vase of yellow chrysanthemums, tall and beautiful, standing just underneath the notice.
He stopped walking. He moved a bit closer. Green curtains (some sort of velvety material) were hanging down on either side of the window. The chrysanthemums looked wonderful beside them.
Here Dahl subtly hints to readers that all is not as it seems at this bed and breakfast. While Billy views the chrysanthemums as “tall and beautiful” and “wonderful,” he ignores (or perhaps is unaware of) the fact that chrysanthemums have historically been used as funeral flowers in Europe and are therefore associated with death.
Instead of interpreting the flowers as a warning about the landlady’s murderous intentions, Billy sees them as a warm invitation, and they are part of the reason he decides to stay at the bed and breakfast (rather than at the popular pub that the train porter recommended to him). Here Dahl highlights how appearances can be deceiving, something that proves to be true about the gentle-seeming yet murderous landlady as well.
Like many horror stories, “The Landlady” is riddled with foreshadowing. One of the most overt examples comes when the landlady hints that, at some point during Billy’s stay, she will be breaking the law, as seen in the following passage:
Very well, then. I’ll leave you now so that you can unpack. But before you go to bed, would you be kind enough to pop into the sitting room on the ground floor and sign the book? Everyone has to do that because it’s the law of the land, and we don’t want to go breaking any laws at this stage in the proceedings, do we?
Here the landlady asks Billy to sign her guest book, facetiously stating that it’s “the law of the land,” before noting that she doesn’t want them to break any laws “at this stage in the proceedings.” Her language here heavily implies that she will be breaking the law later in Billy's stay and, though the story ends on an unresolved note, Dahl makes it clear that the landlady likely ends up breaking the law by killing Billy and stuffing him.
The fact that Billy does not capture the double meaning in her words—or even express concern about her statement—indicates that he has been deceived by the landlady’s feeble appearance and does not think her capable of actually committing a crime.