What is a shrub? A shrub is generally considered to be a medium-to-small-sized woody plant with multiple stems.Most shrubs are under 10 feet tall, with stems that are fewer than 3 inches long. They can beevergreen or deciduous and are a staple of landscape design, adding color, texture and variation tolandscapes and garden beds, There are a massive variety of shrubs, including everareen shrubsflowering shrubs, and more, so you’ re sure to find a shrub to please every gardener!