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{{Taxobox
| color = lightgreen
| name = ''Hedera''
| image = Hedera_hibernica1.jpg
| image_width = 240px
| image_caption = ''Hedera hibernica'' shoot with flower buds
| regnum = [[Plant]]ae
| divisio = [[Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Apiales]]
| familia = [[Araliaceae]]
| subfamilia = [[Aralioideae]]
| genus = '''''Hedera'''''
| genus_authority = [[Carolus Linnaeus|L.]]
| subdivision_ranks = Species
| subdivision =
*''[[Hedera algeriensis]]'' – Algerian Ivy
*''[[Hedera azorica]]'' – Azores Ivy
*''[[Hedera canariensis]]'' – Canaries Ivy
*''[[Hedera caucasigena]]''
*''[[Hedera colchica]]'' – Caucasian Ivy
*''[[Hedera cypria]]''
*''[[Hedera helix]]'' – Common Ivy
*''[[Hedera hibernica]]'' – Irish Ivy
*''[[Hedera maderensis]]'' – Madeiran Ivy
*''[[Hedera maroccana]]''
*''[[Hedera nepalensis]]'' – Himalayan Ivy
*''[[Hedera pastuchowii]]'' – Pastuchov's Ivy
*''[[Hedera rhombea]]'' – Japanese Ivy
*''[[Hedera sinensis]]''
*''[[Hedera taurica]]''
}}
'''''Hedera''''' (English name '''ivy''', plural '''ivies''') is a genus of 15 species of climbing or ground-creeping [[evergreen]] woody plants in the family [[Araliaceae]], native to the [[Macaronesia|Atlantic Islands]], western, central and southern [[Europe]], northwestern [[Africa]] and across central-southern [[Asia]] east to [[Japan]]. On suitable surfaces ([[tree]]s and [[Rock (geology)|rock]] faces), they are able to climb to at least 25–30 [[metre]]s above the basal ground level.
They have two [[leaf]] types, with [[palmate]]ly 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 juvenile and adult shoots also differ, the former being slender, flexible and scrambling or climbing with small roots to affix the shoot to the substrate (rock or tree bark), the latter thicker, self-supporting, and without roots. The [[flower]]s are produced in late autumn, individually small, in 3–5 [[centimetre|cm]] diameter umbels, greenish-yellow, and very rich in [[nectar]], an important late food source for [[bee]]s and other insects; the [[fruit]] are small black berries ripening in late winter, and are an important food for many [[bird]]s, though [[poison]]ous to humans. The [[seed]]s are dispersed by birds eating the fruit. The leaves are eaten by the [[larva]]e of some species of [[Lepidoptera]] such as [[Angle Shades]], [[Lesser Broad-bordered Yellow Underwing]], [[Scalloped Hazel]], [[Small Angle Shades]], [[Small Dusty Wave]] (which feeds exclusively on ivy), [[Swallow-tailed Moth]] and [[Willow Beauty]].
===Taxonomic note===
The species are largely [[Allopatric speciation|allopatric]] and closely related, and all have on occasion been treated as varieties or subspecies of ''H. helix'', the first species described. Several additional species have been described in the southern parts of the former [[Soviet Union]], but are not regarded as distinct by most botanists.
==Uses and cultivation==
Ivies are very popular in cultivation within their native range, both for attracting wildlife, and for their evergreen foliage; many [[cultivar]]s with variegated foliage and/or unusual leaf shape have been selected. They are particularly valuable for covering unsightly walls. Ivies have however proved to be a serious [[invasive species|invasive]] [[weed]] in the parts of [[North America]] where winters are not severe, and their cultivation there is now discouraged in many areas. Similar problems exist in [[Australia]] where the plant was originally cultivated in gardens.
Much has been argued as to whether ivy climbing trees will harm the tree or not; the consensus in Europe is that they do not harm trees significantly, though they may compete for ground nutrients and water to a small extent, and trees with a heavy growth of ivy can be more li
able to [[windthrow]]. Problems are greater in North America, where trees may be overwhelmed by the ivy to the extent they are killed; this could be because ivy in North America, being introduced, is without the natural pests and diseases that control its vigour in its native areas. A more serious problem is that ivy creates a vigorous, dense, shade-tolerant evergreen groundcover (precisely the characteristics for which it is often cultivated) that can spread over large areas and outcompete native vegetation.
Similar concerns are expressed about damage to walls. It is generally considered that a soundly mortared wall is impenetrable to the climbing roots of ivy and will not be damaged, and is also protected from further weathering by the ivy keeping rain off the [[Mortar (masonry)|mortar]]. Walls with already weak or loose mortar may however be badly damaged, as the ivy is able to root into the weak mortar and further break up the wall. Subsequent removal of the ivy can be difficult, and is likely to cause more damage than the ivy itself. Modern mortars that contain [[portland cement]] and little lime are stronger than older mortar mixes that were largely composed of just sand and lime. Most mortar mixes changed to contain portland cement in the 1930s. Soft mortar is still used when laying softer brick.
Regional English names for ivy include Bindwood and Lovestone (for the way it clings and grows over stones and brickwork).
==See also==
*[[Poison ivy]] - unrelated to this genus
==References==
* McAllister, H. (1982). New work on ivies. ''Int. Dendrol. Soc. Yearbook'' 1981: 106-109.
<gallery>
Image:Ivy uf1.jpg|''Hedera helix'' leaves
Image:English Ivy Berries.jpg|''Hedera helix'' berries
Image:Hederafuc hibernica2.jpg|''Hedera hibernica'' fruit
Image:Hedera colchica0.jpg|''Hedera colchica'' flowers
Image:Hedera colchica1.jpg|''Hedera colchica'' foliage
Image:variegated-ivy.jpg|Variegated Ivy
Image:Efeu.jpg|Tempelherrenhaus [[Weimar]]
</gallery>
{{commonscat|Hedera}}
{{wiktionarypar|ivy}}
[[Category:Araliaceae]]
[[Category:Garden plants]]
| color = lightgreen
| name = ''Hedera''
| image = Hedera_hibernica1.jpg
| image_width = 240px
| image_caption = ''Hedera hibernica'' shoot with flower buds
| regnum = [[Plant]]ae
| divisio = [[Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Apiales]]
| familia = [[Araliaceae]]
| subfamilia = [[Aralioideae]]
| genus = '''''Hedera'''''
| genus_authority = [[Carolus Linnaeus|L.]]
| subdivision_ranks = Species
| subdivision =
*''[[Hedera algeriensis]]'' – Algerian Ivy
*''[[Hedera azorica]]'' – Azores Ivy
*''[[Hedera canariensis]]'' – Canaries Ivy
*''[[Hedera caucasigena]]''
*''[[Hedera colchica]]'' – Caucasian Ivy
*''[[Hedera cypria]]''
*''[[Hedera helix]]'' – Common Ivy
*''[[Hedera hibernica]]'' – Irish Ivy
*''[[Hedera maderensis]]'' – Madeiran Ivy
*''[[Hedera maroccana]]''
*''[[Hedera nepalensis]]'' – Himalayan Ivy
*''[[Hedera pastuchowii]]'' – Pastuchov's Ivy
*''[[Hedera rhombea]]'' – Japanese Ivy
*''[[Hedera sinensis]]''
*''[[Hedera taurica]]''
}}
'''''Hedera''''' (English name '''ivy''', plural '''ivies''') is a genus of 15 species of climbing or ground-creeping [[evergreen]] woody plants in the family [[Araliaceae]], native to the [[Macaronesia|Atlantic Islands]], western, central and southern [[Europe]], northwestern [[Africa]] and across central-southern [[Asia]] east to [[Japan]]. On suitable surfaces ([[tree]]s and [[Rock (geology)|rock]] faces), they are able to climb to at least 25–30 [[metre]]s above the basal ground level.
They have two [[leaf]] types, with [[palmate]]ly 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 juvenile and adult shoots also differ, the former being slender, flexible and scrambling or climbing with small roots to affix the shoot to the substrate (rock or tree bark), the latter thicker, self-supporting, and without roots. The [[flower]]s are produced in late autumn, individually small, in 3–5 [[centimetre|cm]] diameter umbels, greenish-yellow, and very rich in [[nectar]], an important late food source for [[bee]]s and other insects; the [[fruit]] are small black berries ripening in late winter, and are an important food for many [[bird]]s, though [[poison]]ous to humans. The [[seed]]s are dispersed by birds eating the fruit. The leaves are eaten by the [[larva]]e of some species of [[Lepidoptera]] such as [[Angle Shades]], [[Lesser Broad-bordered Yellow Underwing]], [[Scalloped Hazel]], [[Small Angle Shades]], [[Small Dusty Wave]] (which feeds exclusively on ivy), [[Swallow-tailed Moth]] and [[Willow Beauty]].
===Taxonomic note===
The species are largely [[Allopatric speciation|allopatric]] and closely related, and all have on occasion been treated as varieties or subspecies of ''H. helix'', the first species described. Several additional species have been described in the southern parts of the former [[Soviet Union]], but are not regarded as distinct by most botanists.
==Uses and cultivation==
Ivies are very popular in cultivation within their native range, both for attracting wildlife, and for their evergreen foliage; many [[cultivar]]s with variegated foliage and/or unusual leaf shape have been selected. They are particularly valuable for covering unsightly walls. Ivies have however proved to be a serious [[invasive species|invasive]] [[weed]] in the parts of [[North America]] where winters are not severe, and their cultivation there is now discouraged in many areas. Similar problems exist in [[Australia]] where the plant was originally cultivated in gardens.
Much has been argued as to whether ivy climbing trees will harm the tree or not; the consensus in Europe is that they do not harm trees significantly, though they may compete for ground nutrients and water to a small extent, and trees with a heavy growth of ivy can be more li
able to [[windthrow]]. Problems are greater in North America, where trees may be overwhelmed by the ivy to the extent they are killed; this could be because ivy in North America, being introduced, is without the natural pests and diseases that control its vigour in its native areas. A more serious problem is that ivy creates a vigorous, dense, shade-tolerant evergreen groundcover (precisely the characteristics for which it is often cultivated) that can spread over large areas and outcompete native vegetation.
Similar concerns are expressed about damage to walls. It is generally considered that a soundly mortared wall is impenetrable to the climbing roots of ivy and will not be damaged, and is also protected from further weathering by the ivy keeping rain off the [[Mortar (masonry)|mortar]]. Walls with already weak or loose mortar may however be badly damaged, as the ivy is able to root into the weak mortar and further break up the wall. Subsequent removal of the ivy can be difficult, and is likely to cause more damage than the ivy itself. Modern mortars that contain [[portland cement]] and little lime are stronger than older mortar mixes that were largely composed of just sand and lime. Most mortar mixes changed to contain portland cement in the 1930s. Soft mortar is still used when laying softer brick.
Regional English names for ivy include Bindwood and Lovestone (for the way it clings and grows over stones and brickwork).
==See also==
*[[Poison ivy]] - unrelated to this genus
==References==
* McAllister, H. (1982). New work on ivies. ''Int. Dendrol. Soc. Yearbook'' 1981: 106-109.
<gallery>
Image:Ivy uf1.jpg|''Hedera helix'' leaves
Image:English Ivy Berries.jpg|''Hedera helix'' berries
Image:Hederafuc hibernica2.jpg|''Hedera hibernica'' fruit
Image:Hedera colchica0.jpg|''Hedera colchica'' flowers
Image:Hedera colchica1.jpg|''Hedera colchica'' foliage
Image:variegated-ivy.jpg|Variegated Ivy
Image:Efeu.jpg|Tempelherrenhaus [[Weimar]]
</gallery>
{{commonscat|Hedera}}
{{wiktionarypar|ivy}}
[[Category:Araliaceae]]
[[Category:Garden plants]]
