Hedera helix

Hedera helix (Common Ivy, English Ivy) is a species of ivy native to most of Europe and western Asia. It is labeled as an invasive species in many parts of the United States, and its sale or import is banned in the state of Oregon.
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==Description==
 
It is an evergreen climbing plant, growing to 20–30 m high where suitable surfaces (trees, cliffs, walls) 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 flowers 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 bees 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 birds, though somewhat poisonous to humans.
There are one to five seeds in each berry, which are dispersed by birds eating the berries.
There are three subspecies:
*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 (Italy, Balkans, Turkey). Plants without rhizomes. Orange-yellow ripe fruit.
*Hedera helix subsp. rhizomatifera</br>    McAllister. Southeast Spain. Plants rhizomatiferous. Purple-black ripe fruit.
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 trichomes, usually smaller and slightly more deeply lobed leaves and somewhat less vigorous growth, though identification is often not easy.The Holly and the Ivy. Shropshire Botanical Society Newsletter Autumn 2000: page 14
==Synonyms==
Hedera helix f. arborescens, Hedera helix f. minima, Hedera helix var. conglomerata, Hedera helix var. crenata, Hedera helix var. minima, Hedera helix var. taurica, Hedera poetarum var. taurica, Hedera taurica
==Common Names==
common ivy, English ivy, Italian ivy, ivy, poet's ivy, yellow-berry ivy, Engelse hedera
==Requirements==
*shade
*damp soil
*
==Characteristics==
*Considered to be aggressively invasive
*Considered a noxious weed in a number of states including Oregon and Washington
*
==References==
Category:Air Filters