Courtesy of Atlas Obscura, a “definitive guide to the world’s wondrous and curious places.”:
“Imagine for a moment that a messenger shows up at the door of your elegantly-appointed Victorian home and hands you a small, ribbon-wrapped bouquet, obviously hand-assembled from somebody’s garden. As an inhabitant of the 21st century, your natural inclination is to be charmed by the gift, and to search for an appropriate vase. As a wealthy inhabitant of the 19th century, your instinct is a little different: you rush for your flower dictionary to decode the secret meaning behind the arrangement.
If it’s a mix of lupins, hollyhocks, white heather, and ragged robin, somebody’s impressed with your imaginative wit and wishes you good luck in all your ambitions. By contrast, a collection of delphiniums, hydrangeas, oleander, basil, and birdsfoot trefoil means you’re heartless (hydrangea) and haughty (delphinium), and I hate you (basil). Beware (oleander) my revenge (birdsfoot trefoil)—the ultimate passive aggressive present.
Maybe somebody sent you a mix of geraniums to ask whether they can expect to see you at the next dance. If you have any striped carnations blooming in your conservatory, you can send them to the enquirer to say, ‘afraid not.'”