From Study Force Dictionary
Herbaceous Plants versus Woody Plants
Theophrastus (about 370 - 285 B.C.) is often called the "Father of Botany." He was a Greek philosopher and naturalist, and pupil of Aristotle. He was the first person to publish an organized classification of Plants. In his Enquiry into Plants he described 480 plants, mostly cultivated, and classified or arranged them into four groups:
1. Herbs (these were further grouped into annuals, biennials, and perennials)
A Woody plant is a perennial tree or shrub. The stem remains above ground during the winter. About 50 % of the plants in the world are woody plants.
A herbaceous Perennial plant has stems that die back to the ground each year. A woody stem also develops secondary tissue and increases in stem diameter.
Woody perennials can be divided into three main types
1. Arborescent = Woody and tree-like in size, usually with a single main trunk or stem. Some people define a tree as anything over 10 feet tall.
2. Shrubby or fruticose = Woody throughout and large, usually with several main stems.
3. Suffrutescent = A semi-shrub. A perennial plant with stems only woody at the base. The woody stems only partially die back each year. Ex. Paeonia suffruticosa.
Herbaceous Plants are often divided into three types
1. Annuals = Plants that complete their life cycle in one year. They grow from seed, produce foliage, flower, and produce fruits and seed in one season. Remember, many perennials that are not winter hardy are grown as annuals. Sometimes these are called horticultural annuals.
2. Biennials = Plants that live for two years from seed. They flower only or mostly in the second year. Alcea rosea or Hollyhock is a biennial, as is Daucus carota, the carrot. Some perennials are short lived and resemble biennials in cultivation. Also, some biennials are cold treated or otherwise manipulated so that they appear as annuals. The common Pansy, Viola x wittrockiana, is often planted in the fall and flowers in late winter or spring.
3. Herbaceous Perennials = Plants that live for 3 years or more. Some perennials are short lived, others will grow well for many years. If grown from seed, many should flower in the following season.