A wine bottle border is long-lasting, colorful, distinctive, sturdy, and can even repel gophers and moles (more on that in a minute).
The process is easy: dig a hole and put in the bottle. Digging a trench makes the process a little faster and more uniform as you place the bottles side by side. Digging individual holes adds a slightly more random look.
There are no rules when creating recycled art in the garden. Burying the bottles with the bottle top in the hole and the bottle bottom above the soil allows the widest part of the bottle to define the border. Placing the bottles with the open end up creates a slender profile. Mixing the orientation combines both aspects.
Burying the wine bottles with the open end facing up can even repel burrowing creatures. The concept is that when wind blows over the bottle top it creates a tone, like the music from a jug band. This creates noise that vibrates through the soil. The theory is that this random annoyance repels animals sensitive to sound, namely gophers and moles. I'm not aware of any studies on wine bottles repelling animals, but the idea seems plausible.
Removing the label beforehand makes for a cleaner look. Soak the bottle in water to loosen the label. Some labels only need a few minutes in water while others need hours. Some labels are plasticized and come off in one piece, others need to be scraped with a knife or thumbnail to remove the paper and glue. It's not hard work but it may take a little time. I placed a number of bottles in a large bucket filled with water to hasten the process.
Spots that border the lawn and could interact with lawn mowers and trimmers pose possible breakage. Spots that border walkways raise potential of someone kicking or tripping over the bottles. Spots that border children's play areas pose risk for the kids.
I've placed some of my bottles in a border around my perennial vegetable bed, the asparagus and rhubarb. That bed isn't tilled and the soil isn't disturbed so the bottles are safe from potential damage. It also sets that bed apart from the rest of the garden, defining its uniqueness.
So if you have a lot of wine bottles or have the potential to collect a lot of wine bottles, consider making a garden border. You'll probably be the first in your neighborhood to have one.