Herbaceous are usually small, flowering plants that come in a wide selection of shapes and colours. There are three categories of herbecous plants; perennials, biennials and annuals, which relate to the life span of the plant.
Herbaceous perennials have stems that die off at the end of the growing year, but parts of the plant underground survive to shoot again next year. These plants can survive year after year, constantly shooting, flowering and dying back. Examples of perennials include Peonys, Hostas and most Grasses.
Herbaceous biennials are similar to perennials in that they have stems that die at the end of the growing year with underground parts that survive, but they differ in that they will will only survive for two growing seasons before flowering and dying completely. Examples of biennials include Sweet Williams and Wall Flowers.
Herbaceous annuals are plants that die completely at the end of the growing season, or after they have flowered and fruited. After this they then grow again from a seed. Examples of annuals include Wheat and Peas.