To deceive someone, to hoodwink or mislead them in an enticing way. Example: “The voters had been led up the garden path too often to take a candidate’s promises seriously.”
The first published instance of ‘lead up the garden,’ so far as we know, is in Ethel Mannin’s Sounding Brass (1926) where it refers to women leading men ‘up the garden’ for the purposes of seduction.
When somebody is being led up the garden path, they may be so lulled by falsehoods and distractions that they barely notice where they are going. Imagine a less than honorable suitor leading an heiress or attractive young girl up a secluded garden path, while he whispers sweet, coaxing compliments in her ear. This would confirm the idea that the phrase comes from courting moves.
One possible origin of the connection of gardens to trickery is the old practice of villages marrying off their most unattractive women by having a groom marrying a veiled bride, only seeing his new wife after the marriage has been completed. Weddings were often held in gardens, so the groom would literally be led up the garden path. Note that the veil is still often used. However, it does not always completely hide the bride’s face from view.
Or, perhaps the phrase refers to someone so distracted by the beauty of the garden that they simply don’t notice anything else.
However, there is an interesting, if odd, offshoot for the phrase. Psycholinguists have adopted the term ‘garden path sentence’ for a sentence that fools the reader by being grammatically correct but written in a way that makes their likely first interpretation of it quite wrong. These garden path sentences are found in written text, since speech patterns and voice emphasis would tend to prevent confusion in oral communication.
A garden path sentence, such as “The old man the boat” (meaning “Old people are the crew of the boat”), is a grammatically correct sentence. At first glance, however, it appears not to make any sense. It’s perhaps only on second glance that a reader realizes the word “man” is being used as a verb, not a noun.
It is a special type of sentence that creates a momentarily ambiguous interpretation because it contains a word or phrase that can be interpreted in multiple ways, causing the reader to begin to believe that a phrase will mean one thing when in reality it means something else.
I’m reminded of the necessity of punctuation, but commas won’t do any good in sentences like these. If I were to find a garden path sentence in my writing, I’d weed it out at once. Writing should be easily understood, not puzzling.