Mini-oasis

Irises around a utility pole near my neighbors' house are in full bloom.

There are quite a few mini-gardens like this one around here. I wonder if they were created because of practical reasons (who wants to mow and weedwack that narrow strip between a sidewalk and street and around utility poles?) or because a gardener just had to have one more patch of soil where to put in even more plants. It's probably a little bit of both.