Hedera helix
Encyclopedia
Hedera helix is a species of ivy
native to most of Europe
and western Asia
. It is labeled as an invasive species
in a number of areas where it has been introduced.
It is an evergreen
climbing plant, growing to 20–30 m high where suitable surfaces (tree
s, cliff
s, wall
s) are available, and also growing as ground cover where there are no vertical surfaces. It climbs by means of aerial rootlets which cling to the substrate.
The leaves
are alternate, 50–100 mm long, with a 15–20 mm petiole
; they are of two types, with palmately five-lobed juvenile leaves on creeping and climbing stems, and unlobed cordate adult leaves on fertile flowering stems exposed to full sun, usually high in the crowns of trees or the top of rock faces.
The flower
s are produced from late summer until late autumn, individually small, in 3–5 cm diameter umbels, greenish-yellow, and very rich in nectar, an important late autumn food source for bee
s and other insects.
The fruit
are purple-black to orange-yellow berries
6–8 mm diameter, ripening in late winter, and are an important food for many bird
s, though somewhat poison
ous to humans.
There are one to five seed
s in each berry, which are dispersed by birds eating the berries.
There are three subspecies
:
The closely related species Hedera canariensis
and Hedera hibernica
are also often treated as subspecies of H. helix, though they differ in chromosome
number so do not hybridise readily. H. helix can be best distinguished by the shape and colour of its leaf trichome
s, usually smaller and slightly more deeply lobed leaves and somewhat less vigorous growth, though identification is often not easy.
northeast to southern Scandinavia
, south to Spain
, and east to Ukraine
and northern Turkey
.
The northern and eastern limits are at about the -2°C winter isotherm, while to the west and southwest, it is replaced by other species of ivy.
. Within its native range, the species is greatly valued for attracting wildlife. The flowers are visited by over 70 species of nectar-feeding insects, and the berries eaten by at least 16 species of birds. The foliage provides dense evergreen shelter, and is also browsed by deer.
Over 30 cultivar
s have been selected for such traits as yellow, white, variegated
(e.g. 'Glacier'), and/or deeply lobed leaves (e.g. 'Sagittifolia'), purple stems, and slow, dwarfed
growth.
The plant is considered invasive
and destructive in parts of Australia and the United States. Its sale, transport or propagation is banned in several places.
. In 1597, the British herbalist John Gerard
recommended water infused with ivy leaves as a wash for sore or watering eyes. The leaves can cause severe contact dermatitis
in some people. People who have this allergy (strictly a Type IV hypersensitivity
) are also likely to react to carrots and other members of the Apiaceae
as they contain the same allergen, falcarinol
.
in many parts of the United States, and its sale or import is banned in the state of Oregon
. Ivies are plants adapted to the laurel forest
, a type of cloud forest
habitat. European Ivy for example, is believed was spread by birds in Europe, that helped to colonize large areas again where it had disappeared during the glaciations.
Laurus nobilis and Ilex aquifolium are widespread relics of the laurisilva
forests that originally covered much of the Mediterranean Basin
when the climate of the region was more humid. Ivy also is a relict plant and one of the survivors of the laurel forest
flora in Europe tertiary
era. Disappeared during the glaciations, Ivy re-colonize large areas when the weather was favorable again.
With a great capacity of adaptation, find more favorable conditions for development and a more similar habitat to their historic european habitat. The ecological requirements of the species, are those of the laurel forest
and like most of their counterparts laurifolia in the world, it is a vigorous species with a great ability to populate the habitat that is conducive. Ivy responded to favourable climatic periods and expanded across the available habitat. Ivy occur as opportunistic species across wide distribution with close vicariant relatives and few species, indicating the recent divergence of this species. The extant Ivy species of this group are relatively young. The expansion is favored by seeds spread by birds.
It is a weed in the Australian state of Victoria.
, H. Helix is considered weedy or invasive in a number of regions and is on the official noxious weed lists of 46 states. Like other invasive vines such as kudzu
, H. helix can grow to choke out other plants and create "ivy deserts". State and county sponsored efforts are encouraging the destruction of ivy in forests of the Pacific Northwest
and the Southern United States
. Its sale or import is banned in Oregon
. Ivy can easily escape from cultivated gardens and invade nearby parks, forests and other natural areas. Ivy can climb into the canopy of trees in such density that the trees fall over from the weight, a problem which does not normally occur in its native range. For this reason, it is especially important to remove ivy from trees, creating "survival rings". In its mature form, dense ivy can destroy habitat for native wildlife and creates large sections of solid ivy where no other plants can develop.
"twist, turn" (see: Helix
).
Ivy
Ivy, plural ivies is a genus of 12–15 species of evergreen climbing or ground-creeping woody plants in the family Araliaceae, native to western, central and southern Europe, Macaronesia, northwestern Africa and across central-southern Asia east to Japan and Taiwan.-Description:On level ground they...
native to most of Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and western Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. It is labeled as an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in a number of areas where it has been introduced.
Description
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...
climbing plant, growing to 20–30 m high where suitable surfaces (tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s, cliff
Cliff
In geography and geology, a cliff is a significant vertical, or near vertical, rock exposure. Cliffs are formed as erosion landforms due to the processes of erosion and weathering that produce them. Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually...
s, wall
Wall
A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into rooms, or protects or delineates a space in the open air...
s) are available, and also growing as ground cover where there are no vertical surfaces. It climbs by means of aerial rootlets which cling to the substrate.
The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are alternate, 50–100 mm long, with a 15–20 mm petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
; they are of two types, with palmately five-lobed juvenile leaves on creeping and climbing stems, and unlobed cordate adult leaves on fertile flowering stems exposed to full sun, usually high in the crowns of trees or the top of rock faces.
The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are produced from late summer until late autumn, individually small, in 3–5 cm diameter umbels, greenish-yellow, and very rich in nectar, an important late autumn food source for bee
Bee
Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...
s and other insects.
The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
are purple-black to orange-yellow berries
Berry
The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....
6–8 mm diameter, ripening in late winter, and are an important food for many bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, though somewhat poison
Poison
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....
ous to humans.
There are one to five seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. 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 in each berry, which are dispersed by birds eating the berries.
There are three subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
:
- Hedera helix subsp. helix. Central, northern and western Europe. Plants without rhizomes. Purple-black ripe fruit.
- Hedera helix subsp. poetarum Nyman (syn. Hedera chrysocarpa Walsh). Southeast Europe and southwest Asia (ItalyItalyItaly , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, BalkansBalkansThe Balkans is a geopolitical and cultural region of southeastern Europe...
, TurkeyTurkeyTurkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
). Plants without rhizomes. Orange-yellow ripe fruit. - Hedera helix subsp. rhizomatifera McAllister. Southeast Spain. Plants rhizomatiferousRhizomeIn botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
. Purple-black ripe fruit.
The closely related species Hedera canariensis
Hedera canariensis
Hedera canariensis is a species of Ivy which is native to the Atlantic coast in Canary islands and northern Africa. Its common name is the Canarian Ivy.-Description:...
and Hedera hibernica
Hedera hibernica
Hedera hibernica is a species of Ivy which is native to the Atlantic coast of Europe. Its common names are the Atlantic Ivy or Irish Ivy.-Overview:...
are also often treated as subspecies of H. helix, though they differ in chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
number so do not hybridise readily. H. helix can be best distinguished by the shape and colour of its leaf trichome
Trichome
Trichomes are fine outgrowths or appendages on plants and certain protists. These are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae.- Algal trichomes :...
s, usually smaller and slightly more deeply lobed leaves and somewhat less vigorous growth, though identification is often not easy.
Range
It ranges from IrelandIreland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
northeast to southern Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
, south to Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
, and east to Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...
and northern Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
.
The northern and eastern limits are at about the -2°C winter isotherm, while to the west and southwest, it is replaced by other species of ivy.
Cultivation and uses
It is widely cultivated as an ornamental plantOrnamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...
. Within its native range, the species is greatly valued for attracting wildlife. The flowers are visited by over 70 species of nectar-feeding insects, and the berries eaten by at least 16 species of birds. The foliage provides dense evergreen shelter, and is also browsed by deer.
Over 30 cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s have been selected for such traits as yellow, white, variegated
Variegation
Variegation is the appearance of differently coloured zones in the leaves, and sometimes the stems, of plants. This may be due to a number of causes...
(e.g. 'Glacier'), and/or deeply lobed leaves (e.g. 'Sagittifolia'), purple stems, and slow, dwarfed
Dwarfing
Dwarfing is a characteristic in plants and animals whereby one or more members of a breed or cultivar are significantly smaller than standard members of their species...
growth.
The plant is considered invasive
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
and destructive in parts of Australia and the United States. Its sale, transport or propagation is banned in several places.
Ethnomedical uses
In the past, the leaves and berries were taken orally as an expectorant to treat cough and bronchitisBronchitis
Acute bronchitis is an inflammation of the large bronchi in the lungs that is usually caused by viruses or bacteria and may last several days or weeks. Characteristic symptoms include cough, sputum production, and shortness of breath and wheezing related to the obstruction of the inflamed airways...
. In 1597, the British herbalist John Gerard
John Gerard
John Gerard aka John Gerarde was an English herbalist notable for his herbal garden and botany writing. In 1597 he published a large and heavily illustrated "Herball, or Generall Historie of Plantes", which went on to be the most widely circulated botany book in English in the 17th century...
recommended water infused with ivy leaves as a wash for sore or watering eyes. The leaves can cause severe contact dermatitis
Contact dermatitis
Contact dermatitis is a term for a skin reaction resulting from exposure to allergens or irritants . Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight....
in some people. People who have this allergy (strictly a Type IV hypersensitivity
Type IV hypersensitivity
Type IV hypersensitivity is often called delayed type hypersensitivity as the reaction takes two to three days to develop. Unlike the other types, it is not antibody mediated but rather is a type of cell-mediated response....
) are also likely to react to carrots and other members of the Apiaceae
Apiaceae
The Apiaceae , commonly known as carrot or parsley family, is a group of mostly aromatic plants with hollow stems. The family is large, with more than 3,700 species spread across 434 genera, it is the sixteenth largest family of flowering plants...
as they contain the same allergen, falcarinol
Falcarinol
Falcarinol is a natural pesticide and fatty alcohol found in carrots, red ginseng and ivy. It protects roots from fungal diseases, such as liquorice rot that causes black spots on the roots during storage. Falcarinol is a polyyne with two carbon carbon triple bonds and two double bonds...
.
Invasive species
Like other exotic species, the invasion is due to human actions. H. helix is labeled as an invasive speciesInvasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in many parts of the United States, and its sale or import is banned in the state of Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
. Ivies are plants adapted to the laurel forest
Laurel forest
Laurel forest is a subtropical or mild temperate forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterized by tree species with evergreen, glossy, enlongated leaves, known as laurophyll or lauroide...
, a type of cloud forest
Cloud forest
A cloud forest, also called a fog forest, is a generally tropical or subtropical evergreen montane moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests often exhibit an abundance of mosses covering the ground and...
habitat. European Ivy for example, is believed was spread by birds in Europe, that helped to colonize large areas again where it had disappeared during the glaciations.
Laurus nobilis and Ilex aquifolium are widespread relics of the laurisilva
Laurisilva
Laurisilva or laurissilva is a subtropical forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterised by evergreen, glossy-leaved tree species that look alike with leaves of lauroide type...
forests that originally covered much of the Mediterranean Basin
Mediterranean Basin
In biogeography, the Mediterranean Basin refers to the lands around the Mediterranean Sea that have a Mediterranean climate, with mild, rainy winters and hot, dry summers, which supports characteristic Mediterranean forests, woodlands, and scrub vegetation...
when the climate of the region was more humid. Ivy also is a relict plant and one of the survivors of the laurel forest
Laurel forest
Laurel forest is a subtropical or mild temperate forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterized by tree species with evergreen, glossy, enlongated leaves, known as laurophyll or lauroide...
flora in Europe tertiary
Tertiary
The Tertiary is a deprecated term for a geologic period 65 million to 2.6 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...
era. Disappeared during the glaciations, Ivy re-colonize large areas when the weather was favorable again.
With a great capacity of adaptation, find more favorable conditions for development and a more similar habitat to their historic european habitat. The ecological requirements of the species, are those of the laurel forest
Laurel forest
Laurel forest is a subtropical or mild temperate forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterized by tree species with evergreen, glossy, enlongated leaves, known as laurophyll or lauroide...
and like most of their counterparts laurifolia in the world, it is a vigorous species with a great ability to populate the habitat that is conducive. Ivy responded to favourable climatic periods and expanded across the available habitat. Ivy occur as opportunistic species across wide distribution with close vicariant relatives and few species, indicating the recent divergence of this species. The extant Ivy species of this group are relatively young. The expansion is favored by seeds spread by birds.
Australia
It is considered a noxious weed across southern, particularly south-eastern, Australia and local councils provide free information and limited services for removal. In some councils it is illegal to sell the plant.It is a weed in the Australian state of Victoria.
New Zealand
H. helix has been listed as a weed by the Department of Conservation since 1990.United States
In the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, H. Helix is considered weedy or invasive in a number of regions and is on the official noxious weed lists of 46 states. Like other invasive vines such as kudzu
Kudzu in the United States
Kudzu is a serious invasive plant in the United States. It has been spreading in the southern U.S. at the rate of annually, "easily outpacing the use of herbicide spraying and mowing, as well increasing the costs of these controls by $6 million annually." Its introduction has produced devastating...
, H. helix can grow to choke out other plants and create "ivy deserts". State and county sponsored efforts are encouraging the destruction of ivy in forests of the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
and the Southern United States
Southern United States
The Southern United States—commonly referred to as the American South, Dixie, or simply the South—constitutes a large distinctive area in the southeastern and south-central United States...
. Its sale or import is banned in Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
. Ivy can easily escape from cultivated gardens and invade nearby parks, forests and other natural areas. Ivy can climb into the canopy of trees in such density that the trees fall over from the weight, a problem which does not normally occur in its native range. For this reason, it is especially important to remove ivy from trees, creating "survival rings". In its mature form, dense ivy can destroy habitat for native wildlife and creates large sections of solid ivy where no other plants can develop.
Etymology
Hedera is the generic term for Ivy. The species name helix derives from Ancient GreekAncient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
"twist, turn" (see: Helix
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...
).