Retired professor Allan Armitage is a renowned horticulturist and a columnist for Greenhouse Gardener. He recently wrote an article about the increased interest in gardening during COVID. He observes that everyone is getting older. They are focused on plants and vegetables for containers, as well as the containers themselves. There is a low maintenance trend toward compact plants that do not need staking. The dahlia hybridizers are responding, and the garden centers are just receiving dozens of compact and attractive dahlias in virtually every form.
Try one of the new micros, such as U2 Fire pictured above left. The bloom is about 2" across with a slim, 24" high plant. Looks great in a large flower pot.
Design tip: Make an artistic statement anywhere. Group together an odd number of pots, with plants of different heights, one variety (can be multiple plants) per pot.