Hardiness (plants)
Encyclopedia
Hardiness of plant
s describe their ability to survive adverse growing conditions. It is usually limited to discussions of climatic adversity. Thus a plant's ability to tolerate cold
, heat
, drought
, flood
ing, or wind
are typically considered measurements of hardiness. Hardiness of plants is defined by their native extent's geographic location: longitude
, latitude
and elevation
. These attributes are often simplified to a hardiness zone
. In temperate
latitudes, the term most often describes resistance to cold, or "cold-hardiness," and is generally measured by the lowest temperature a plant can withstand. Hardiness of a plant is usually divided into three categories: tender, half-hardy, and hardy. Tender plants are those killed by freezing temperatures, while hardy plants survive freezing—at least down to certain temperatures, depending on the plant.
Plants vary a lot in their tolerance of growing conditions. The selective breeding
of varieties capable of withstanding particular climates forms an important part of agriculture
and horticulture
. Plants adapt to changes in climate on their own to some extent. Part of the work of nursery growers of plants consists of cold hardening
, or hardening off their plants, to prepare them for likely conditions in later life.
, or at least remain healthy and dormant
. Apart from the obvious evergreen
s, these include many cultivated plants, including some cabbage
and broccoli
, and all kinds of carrot
. Some bulbs – such as tulip
s – need cold winters in order to bloom, while others – such as freesia
– can survive a freezing winter. Many domestic plants are assigned a hardiness zone
that specifies the climates in which they can survive. Winter garden
s are dependent upon the cultivation of winter-hardy plants.
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
s describe their ability to survive adverse growing conditions. It is usually limited to discussions of climatic adversity. Thus a plant's ability to tolerate cold
Cold
Cold describes the condition of low temperature.Cold may also refer to:*Common cold, a contagious viral infectious disease of the upper respiratory system*Chronic obstructive pulmonary disease...
, heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
, drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
, flood
Flood
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...
ing, or wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
are typically considered measurements of hardiness. Hardiness of plants is defined by their native extent's geographic location: longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
, latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
and elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
. These attributes are often simplified to a hardiness zone
Hardiness zone
A hardiness zone is a geographically defined area in which a specific category of plant life is capable of growing, as defined by climatic conditions, including its ability to withstand the minimum temperatures of the zone...
. In temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
latitudes, the term most often describes resistance to cold, or "cold-hardiness," and is generally measured by the lowest temperature a plant can withstand. Hardiness of a plant is usually divided into three categories: tender, half-hardy, and hardy. Tender plants are those killed by freezing temperatures, while hardy plants survive freezing—at least down to certain temperatures, depending on the plant.
Plants vary a lot in their tolerance of growing conditions. The selective breeding
Selective breeding
Selective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains that are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties,...
of varieties capable of withstanding particular climates forms an important part of agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
and horticulture
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
. Plants adapt to changes in climate on their own to some extent. Part of the work of nursery growers of plants consists of cold hardening
Cold hardening
Cold hardening is the physiological and biochemical process by which an organism prepares for cold weather.-Plants:During the winter months, as the leaves fall off deciduous species and the temperature drops, the cold forces a stop to water movement in plants. Freezing water can also cause...
, or hardening off their plants, to prepare them for likely conditions in later life.
Winter hardiness
Winter-hardy plants grow during the winterWinter
Winter is the coldest season of the year in temperate climates, between autumn and spring. At the winter solstice, the days are shortest and the nights are longest, with days lengthening as the season progresses after the solstice.-Meteorology:...
, or at least remain healthy and dormant
Dormancy
Dormancy is a period in an organism's life cycle when growth, development, and physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions...
. Apart from the obvious evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
s, these include many cultivated plants, including some cabbage
Cabbage
Cabbage is a popular cultivar of the species Brassica oleracea Linne of the Family Brassicaceae and is a leafy green vegetable...
and broccoli
Broccoli
Broccoli is a plant in the cabbage family, whose large flower head is used as a vegetable.-General:The word broccoli, from the Italian plural of , refers to "the flowering top of a cabbage"....
, and all kinds of carrot
Carrot
The carrot is a root vegetable, usually orange in colour, though purple, red, white, and yellow varieties exist. It has a crisp texture when fresh...
. Some bulbs – such as tulip
Tulip
The tulip is a perennial, bulbous plant with showy flowers in the genus Tulipa, which comprises 109 species and belongs to the family Liliaceae. The genus's native range extends from as far west as Southern Europe, North Africa, Anatolia, and Iran to the Northwest of China. The tulip's centre of...
s – need cold winters in order to bloom, while others – such as freesia
Freesia
Freesia Ecklon ex Klatt is a genus of 14–16 species of flowering plants in the family Iridaceae, native to Africa. Of the 14 species, 12 are native to Cape Province, South Africa, the remaining two to tropical Africa, one species extending north of the equator to Sudan.The genus was named in honor...
– can survive a freezing winter. Many domestic plants are assigned a hardiness zone
Hardiness zone
A hardiness zone is a geographically defined area in which a specific category of plant life is capable of growing, as defined by climatic conditions, including its ability to withstand the minimum temperatures of the zone...
that specifies the climates in which they can survive. Winter garden
Winter garden
The origin of the winter garden dates back to the 17th to 19th centuries where European nobility would construct large conservatories that would house tropical and subtropical plants and would act as an extension of their living space. Many of these would be attached to their main palaces...
s are dependent upon the cultivation of winter-hardy plants.