I have never seen a pickle on a tree, but apparently, it is a "thing"!
It is said to be a fortuitous sighting and part of an old world holiday that has its roots in Germany.
I am sure I would have been introduced to this having two German Au Pairs over the years, but this is the first I have heard of the pickle ornament. So, of course, I had to investigate and saw that according to the NY times they polled 2,057 Germans, and YouGov did determine that 91% were unaware of the legend.
Popular in the Midwest, maybe some German immigrants in Berrien Springs Michigan, which is a German Settlement have something to do with that. They have a Christmas Pickle Festival, and it is the Christmas Pickle Capital of the World.
So where did this story come from?
Several different stories are out there from boys getting put in a pickle barrel to a prisoner in the Civil war who begged for one last pickle.
The story I find most plausible is in the 1880's Woolworth started selling glass ornaments from Germany that were fruits and vegetables. A Pickle was among the selection. Around the same time, it was claimed that the tradition of the Christmas pickle was that it was the last ornament hung on the tree and the first child to find the pickle wins a prize.
It sounds like Woolworth had a creative salesperson for low pickle ornament sales, but that is just me- who am I to question tradition.
While you are out at holiday parties and gathering; see if you can spot the pickle ornament- you might just win a prize!