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Biennial plant

 
Biennial Plant

 
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Biennial plant
 
 
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A biennial plant is a flowering plant that takes two years to complete its biological lifecycle. In the first year the plant grows leaves, stems, and roots (vegetative structures), then it enters a period of dormancy over the colder months. Usually the stem remains very short and the leaves are low to the ground, forming a rosette.






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Parsley Curled
A biennial plant is a flowering plant that takes two years to complete its biological lifecycle. In the first year the plant grows leaves, stems, and roots (vegetative structures), then it enters a period of dormancy over the colder months. Usually the stem remains very short and the leaves are low to the ground, forming a rosette. Many biennials require a cold treatment, or vernalization
Vernalization

Vernalization is the acquisition of the competence to flower in the spring by exposure to the prolonged cold of winter. The word vernalization comes from the Latin word vernus, meaning of the spring ....
, before they will flower. During the next spring or summer, the stem of the biennial plant elongates greatly, or "bolting bolts". The plant then flowers, producing fruits and seed
Seed

A seed is a small Plant embryogenesis plant enclosed in a covering called the seed coat, usually with some Food storage. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant....
s before it finally dies. There are far fewer biennials than either perennial plants or annual plants.

Under extreme climatic conditions, a biennial plant may complete its life cycle in a very short period of time (e.g. three or four months instead of two years). This is quite common in vegetable or flower seedlings that were exposed to cold conditions, or vernalized, before they were planted in the ground. This behavior leads to many normally biennial plants being treated as annuals
Annual plant

An annual plant is a plant that usually germinates flowers and dies in one year. True annuals will only live longer than a year if they are prevented from setting seed....
 in some areas. Flowering can be induced in some biennials without vernalization by application of the plant hormone
Plant hormone

Plant hormones are chemicals that regulate plant growth. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations....
 gibberellin
Gibberellin

Gibberellins are plant hormones that regulate growth and influence various Biological process, including "stem elongation, germination, dormancy, flowering, sex gene expression, enzyme induction and leaf and fruit senescence."...
, but this is rarely done commercially.

From a gardener's perspective, a plant's status as annual
Annual plant

An annual plant is a plant that usually germinates flowers and dies in one year. True annuals will only live longer than a year if they are prevented from setting seed....
, biennial, or perennial
Perennial plant

A perennial plant or perennial is a plant that lives for more than two years. When used by gardeners or horticulturalists, this term applies specifically to perennial herbaceous plants....
 often varies based on location or purpose. Biennials grown for flowers, fruits, or seeds need to be grown for two years. Biennials that are grown for edible leaves or roots are grown as annuals, e.g. beet
Beet

The beet is a plant in the Amaranthaceae. It is best known its numerous cultivated varieties, the most well known of which is probably the red root vegetable known as the garden beet....
s, Brussels sprouts, cabbage
Cabbage

The cabbage is a leafy garden plant of the Family Brassicaceae , used as a Leaf vegetable. It is a herbaceous, biennial plant, dicotyledonous flowering plant distinguished by a short stem upon which is crowded a mass of leaves, usually green but in some varieties red or purplish, forming a characteristic compact, globular cluster ....
, carrot
Carrot

The carrot is a root vegetable, usually orange or white, or red-white blend in colour, with a crisp texture when fresh. The edible part of a carrot is a taproot....
s, celery
Celery

Apium graveolens is a plant species in the family Apiaceae commonly known as celery or celeriac depending on whether the petioles or roots are eaten....
, lettuce
Lettuce

Lettuce is a temperate annual plant or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. In many countries, it is typically eaten cold, raw, in salads, hamburgers, tacos, and in many other dishes....
, parsley
Parsley

Parsley is a bright green, biennial plant herb, also used as spice. It is very common in Middle Eastern cuisine, European cuisine, and American cuisine cooking....
, and Swiss chard. If a normally biennial plant is grown in extremely harsh conditions, it is likely to be treated as an annual because it will not survive the winter cold. Conversely, an annual grown under extremely favorable conditions may have highly successful seed propagation, giving it the appearance of being biennial or perennial. Some short-lived perennials may appear to be biennial rather than perennial. True biennials flower only once, while many perennials will flower every year once mature.

Examples of biennial plants are parsley
Parsley

Parsley is a bright green, biennial plant herb, also used as spice. It is very common in Middle Eastern cuisine, European cuisine, and American cuisine cooking....
, Lunaria
Lunaria

Lunaria is a genus of flowering plants in the family Brassicaceae, native to central and southern Europe. It includes two species, Perennial honesty and Annual honesty....
, silverbeet, Sweet William
Sweet William

Dianthus barbatus is a species of Dianthus native to the mountains of southern Europe from the Pyrenees east to the Carpathian Mountains and the Balkans, with a variety disjunct in northeastern China, Korea, and southeasternmost Russia....
, colic weed
Colic weed

Colic weed may refer to:* Aletris spp.* Corydalis flavula* Dicentra spp....
, and carrot
Carrot

The carrot is a root vegetable, usually orange or white, or red-white blend in colour, with a crisp texture when fresh. The edible part of a carrot is a taproot....
. Plant breeders have produced annual cultivars of several biennials that will flower the first year from seed, e.g. foxglove and stock
Matthiola incana

Matthiola incana is one of several species of Matthiola, and is sometimes called hoary stock. It is a common garden flower, available in a variety of colours....
.

See also

  • Annual plant
    Annual plant

    An annual plant is a plant that usually germinates flowers and dies in one year. True annuals will only live longer than a year if they are prevented from setting seed....
  • Perennial plant
    Perennial plant

    A perennial plant or perennial is a plant that lives for more than two years. When used by gardeners or horticulturalists, this term applies specifically to perennial herbaceous plants....