How to Grow Asparagus
Asparagus is a plant of the lily family native to Eurasia but now raised in most parts of the world for its edible young stems. The common, or garden, asparagus is a perennial plant which, (1.2 to 3 meters). Its stems, commonly called spears, are the part of the plant used for food. The tips of the thick, fleshy stems are covered with many small, scale-like leaves. Each spring, new spears grow from horizontal underground steins called rhizomes. If the spears are not cut, they mature into slender, tough stalks with many feather-like branches. The bell-shaped flowers of the matured plant are yellow-green and grow singly, or in groups of up to four. The small greenish flowers ripen into a red fruit, called a berry.
When an asparagus crop is started, the plants are raised from seeds that are grown in a nursery seedbed until they are at least one or two years old. At that time their crowns, or underground rootstocks, are transplanted to a field.
The crowns are planted several inches below the ground, and those that are to be harvested as white shoots are planted in rows that are ridged or hilled up so that the growing shoots will be shielded from the sun and will not turn green.
Asparagus plants grown in areas with a continuous growing season are spindly and become exhausted more rapidly than those grown in temperate regions.
Generally, a field that is well cultivated should be productive for 10 to 15 years.
Asparagus plants make up the genus Asparagus of the family Liliaceae (lily), and there are more than 150 species. The common asparagus is classified as Asparagus officinalis. The asparagus fern is Asparagus plumosus, and the florist's species is Asparagus asparagoides. Another popular ornamental is Asparagus sprengeri.
Some species, such as the asparagus fern, are often grown for their decorative value, and one species is used in the florist trade, where it is erroneously known as smilax.
The leading producers of asparagus are the United States and Taiwan. In the United States, most of the asparagus is grown in California and Washington.