The first "stringless" bean was bred in 1894 by Calvin Keeney, called the "father of the stringless bean," while working in
Le Roy, New York. Most modern green bean varieties do not have strings.
Plant Green beans are classified by growth habit into two major groups, "bush" (or "dwarf") beans and "pole" (or "climbing") beans. Bush beans are short plants, growing to not more than in height, often without requiring supports. They generally reach maturity and produce all of their fruit in a relatively short period, then cease to produce. Owing to this concentrated production and ease of mechanized harvesting, bush-type beans are those most often grown on commercial farms. Bush green beans are usually cultivars of the common bean (
Phaseolus vulgaris). Pole beans have a climbing habit and produce a twisting vine, which must be supported by "poles,"
trellises, or other means. Pole beans may be common beans (
Phaseolus vulgaris), runner beans (
Phaseolus coccineus) or yardlong beans (
Vigna unguiculata subsp.
sesquipedalis).
Half-runner beans have both bush and pole characteristics, and are sometimes classified separately from bush and pole varieties. Their runners can be about long.
Varieties Over 130 varieties (cultivars) of edible pod beans are known. Varieties specialized for use as green beans, selected for the succulence and flavor of their green pods, are the ones usually grown in the home vegetable garden, and many varieties exist. Beans with various pod colors (green, purple, red, or streaked.) are collectively known as snap beans, while green beans are exclusively green. Pod shapes range from thin and circular ("fillet" types) to wide and flat ("romano" types) and more common types in between. The three most commonly known types of green beans belonging to the species
Phaseolus vulgaris are string or snap beans, which may be round or have a flat pod; stringless or French beans, which lack a tough, fibrous string running along the length of the pod; and runner beans, which belong to a separate species,
Phaseolus coccineus. Green beans may have a purple rather than green pod, which changes to green when cooked. Yellow-podded green beans are also known as
wax beans. Wax bean cultivars are commonly of the bush or dwarf form. All of the following varieties have green pods and are
Phaseolus vulgaris unless otherwise specified:
Bush (dwarf) types Pole (climbing) types == Production ==