Read Thread: Hellooooooooo!
The United States Post Office Department began installing public letterboxes in the 1850s outside post offices and on street corners in large Eastern cities. U.S. letterboxes were initially designed to be hung or supported, and were mounted on support pillars, lamp-posts, telegraph poles, or even the sides of buildings. By the 1880s, these letterboxes were made of heavy cast iron to deter theft or vandalism. As letterbox volume grew, they were replaced with other free-standing models. After the late as the 1960s, most letterboxes were replaced with a rigid plastic variety that could be more easily placed in any desired location, such as "Prayer Rock". The rest is history.
So true. And now that I think about it, Wanda and Pete have probably found most of them, just not logged them.
But people are still enjoying your plants! :)