This includes the ornamental plants we commonly call perennials such as daylilies, peonies and coneflowers as well as all the trees and shrubs. The annuals, biennials and perennials are also divided into either herbaceous or woody categories. Herbaceous plants have soft, non-woody growth and they die back to the ground at the end of the growing season. Technically annuals are herbaceous but this term is generally reserved for plants that are perennial. Woody plants are those that develop bark, a thick, woody covering on their twigs and branches.
Most woodies are either trees, shrubs or vines .
As with so many concepts, there are exceptions to these definitions. A beautiful clump of birch is a tree, not a shrub as the strict definitions would suggest. A vine is any plant that cannot support its own growth. It can be woody or herbaceous. There are many other ways of grouping similar plants together.