Pavement serves a purpose in a landscape. So does decking. They are the flooring of the outdoor spaces that are used for outdoor living. Patios and decks are where we barbecue and dine. Walkways and porches are how we get around the exteriors of our homes. Driveways are where we park cars. For what they get used for, they are better than turf grass, ground cover or bare soil.
So why is it so trendy to clutter pavement and decking with potted plants that would really prefer to be in the ground? It would be more practical to pave less area, and leave more space to plant things in the ground. There would be no damp pots staining concrete or rotting decking. There would be less area to rake or blow, with fewer obstacles in the way. Watering would be much easier.
Well, as it turns out, there are a few plants that should be potted. Houseplants are the most obvious. After all, not many homes have exposed soil where houseplants can be grown on the inside. Even if they did, it is still easier to keep houseplants potted for portability. Plants such as orchids and Christmas cactus, can live in the garden most of the time, and then come in while blooming. Portability is also important for tropical plants that need protection from even mild frost. It might be easier to move them than to cover them.
There are also a few plants that are contained because they are invasive. Mint and horseradish are culinary plants that are so famously invasive that not many of us would bother growing them if they were not so much better fresh from the garden than purchased from elsewhere. Rather than allow them to escape, mint is popularly potted, and horseradish is commonly grown in deep tubs.
Container gardening and growing plants in pots is something that we do for out own convenience, or just because it looks good cluttering otherwise useful parts of the landscape. With only a few exceptions, plants prefer to be in the ground, where they can disperse their roots as extensively as they like. They are healthier, and need less attention. To them, container gardening is unnatural.