If you really want to add columns to the number of design features you already have in your home, but there seems to be absolutely no aesthetic or structural justification for their use (it can happen!), take a look at your outside space. Garden columns are an old time favorite when it comes to dividing different areas in a park or simply providing some architectural interest. It is often that these columns do not perform any utilitarian function whatsoever. They can literally be freestanding, provided that their capitals are elaborate and visually appealing in their own right.
Still, it is much better if you can use your garden columns as planters or as support for hanging plants. Short columns that can be used as planter bases are often called pedestals. Such short columns can also look great in combination with sculptures, bird baths and solar lights.
You can even go for a ruin look that was very popular in Renaissance times and in Romantic gardens. Believe it or not, columns are actually manufactured to look broken and aged: