Akebia quinata

Chocolate vine (Akebia quinata)
Common names	Chocolate vine, five-leaf akebia, five-leaf chocolate vine, raisin vine, akebi
Scientific name	Akebia quinata
Family	Lardizabalaceae
Genus	Akebia
Order	Ranunculales
Native range	Central and eastern China to central and southern Japan, and Korea
Growth habit	Twining woody climber to about 10 m (to 12 m), deciduous to semi-evergreen
Fruit	Sausage-shaped purplish pod to about 10 cm, opening to sweet white pulp around many black seeds
Pollination	Monoecious but self-incompatible; two genetically different vines or hand pollination
Years to fruit	About 1–2 years
Harvest season	Autumn (September–October in North America and Europe)
Hardiness	About USDA zones 5a–8b; dormant wood to about −20 °C
Uses	Fresh pulp, cooked rind and shoots, tea substitute; ornamental vine

Akebia quinata, the chocolate vine (also five-leaf akebia, five-leaf chocolate vine or raisin vine; akebi in Japanese), is a twining woody climber of the family Lardizabalaceae. The name was published in 1839 and is the accepted one today; the original name Rajania quinata is a synonym. ^[1] The native range runs from central and eastern China to central and southern Japan, with Korea also recorded. ^[1] In the wild it grows along forest margins beside streams and in scrub on mountain slopes between about 300 and 1500 m. ^[2] Grown for its fragrant early flowers and vigorous cover as an ornamental, it is also cultivated for its edible fruit.

Description

The vine is a woody climber, deciduous to semi-evergreen, reaching about 10 m and quoted at 8–12 m in cultivation. ^[6] Stems are grayish-brown with rounded lenticels. ^[2] The palmately compound leaves carry (3–)5(–7) obovate to obovate-elliptic, papery leaflets that are glaucous on the lower surface; horticultural accounts give five leaflets of 1–3 in (2.5–7.5 cm). ^[2][5] The vine climbs by twining and, like others in the genus, needs a support unless it is used as a ground cover. ^[5][9]

Flowers are unisexual and monoecious, with male and female flowers in the same drooping raceme. ^[2] The inflorescences usually carry 4–10 male flowers and 1–2 female flowers; a female flower typically holds 4–10 divergent carpels with about 200 ovules each, and the male flowers open one to two days after the females, overlapping for about a week. ^[3] There are no true petals; the three (rarely five) petaloid sepals are pale purple in the male flowers and dark purple, 1–2 × 0.8–1.5 cm, in the female flowers. ^[2] Descriptions call the flowers reddish-purple and fragrant, in racemes about 12 cm long, with a scent recalled as chocolate or vanilla. ^[6][9]

The fruit is a purplish, sausage-shaped pod, straight or slightly curved, 5–8 × 3–4 cm in the Chinese flora and up to about 10 cm in cultivation. ^[2][6] It splits open in autumn to reveal sweet white pulp and many small, compressed, shiny brown-to-black seeds. ^[2][4]

Cultivation

Soil and water

Native stations are streamside forest margins and slope scrub between 300 and 1500 m — well-drained but reliably moist ground. ^[2] In gardens the vine grows in most soil types; Missouri Botanical Garden finds it easiest in a well-drained sandy loam with regular moisture, and CABI records a preference for well-drained yet moist soils from sandy to clay in texture and acid to alkaline in pH. ^[5][7] Once established it tolerates some drought. ^[5][7] The roots resent disturbance, so young plants set out promptly from containers transplant better than older root-balls. ^[8]

Sun and humidity

The vine is flexible about light, growing in deep shade to full sun, with full sun to part shade favored for flowering. ^[4][5] It is shade and drought tolerant once settled, ^[7] but heavy shade suppresses bloom, and a Boise, Idaho (zone 6) grower reports no flowers in deep shade with heavy flowering and fruiting in full sun. ^[13]

Seasonal changes

The vine is semi-evergreen in mild winters and largely deciduous in colder ones, with new leaves and flower racemes appearing together in early spring. ^[9][6] New spring growth is frost-tender even though dormant wood is hardy to about −20 °C; light frosts can kill the fresh shoots, so a sheltered site matters where late frosts are common. ^[7][8] A Kansas grower reports that the vines struggled badly at first, and cold snaps killed young vines to the ground in another grower's account. ^[12] RHS gives the species hardiness rating H6 (about −20 °C) and assigns the fruiting cultivars the same requirement of long, hot summers and a second plant to fruit well. ^[6][10][11]

Flowering in the Chinese flora runs April–May with fruiting June–August; the study population in central China flowered March–May, and fruit took about four months to ripen. ^[2][3] In North America and Europe the pods open in autumn, roughly September–October. ^{[4][8][13][15]} Invasive-potential reports follow the same vigor: the vine is fast, smothering near supports, and is listed as invasive by the North Carolina Invasive Plant Council, so it should be planted where spread can be managed rather than near beds or open woodland it could blanket. ^[4][7][12]

Propagation

Fresh seed germinates readily: surface-sown fresh seed sprouts in one to three months at about 15 °C, while stored seed benefits from about a month of cold stratification and can still be difficult. ^[8] Seedlings vary, because open-pollinated seed is hybrid seed: a Boise grower who raised seedlings from two parent vines reports the seedlings have spread widely but not fruited. ^[13] Vegetative routes are useful to keep a chosen plant: half-ripe cuttings in July–August root slowly, softwood cuttings root in spring, root cuttings taken in December root in a warm greenhouse, and layering in early spring is very easy because the plants usually self-layer. ^[8] Growers confirm the ground-layering habit, with vines rooting wherever stems touch soil. ^[9][12] Because the roots resent disturbance, start plants in containers and plant them out young. ^[8]

Flowering, fruiting, and harvest

Flowers are functionally unisexual and the species is late-acting self-incompatible: self-pollen reaches the ovules but does not fertilize them, so a single vine, or two cuttings of the same clone, produces little or no fruit. ^[3] Geitonogamy (self-pollination between flowers of one plant) is common in the wild — in a two-population Chinese study 65% of flowers carried self-pollen, most stigmas were pollen-limited, and natural mature fruit set was only about 1.2%. In hand-pollination trials, young fruit set fell from about 0.85 with pure cross-pollen to 0.18 when self-pollen dominated the mix, while a little self-pollen alongside cross-pollen did no harm. ^[3]

In practice this means planting at least two genetically different vines, and often hand-pollinating. Extension and botanic-garden sources say flowers must be cross-pollinated by a different plant and recommend hand-pollination for reliable fruit, and cultivar profiles repeat that two plants of the species are needed. ^{[4][5][10][11]} A western Washington (zone 8b) grower hand-pollinates and reports several hundred fruit in ordinary years and well under ten in the year pollination was skipped; the same grower notes heavy bearing from one vine and none from a second. ^[12] Reported pollination is carried mainly by hoverflies, honey bees and small solitary bees, with wind suspected. ^[7] A Reddit grower in the UK fruited an unnamed normal vine paired with an 'Alba', while a commenter whose 'Alba' and purple-flowered plants flowered at different times got no cross-pollination — bloom overlap matters when pairing clones. ^[14]

Vines can bear in the first or second year; orchard-scale summaries describe a short juvenile period of about two years before heavy fruiting. ^[13][7] The pods split open naturally on the vine when ripe and should be picked then — they do not fall at ripeness, over-ripe fruit dries on the vine, and opened fruit is perishable, with mold reported when rain enters split pods. ^[13][14]

Fruit and uses

The pulp is sweet with a delicate flavor. ^[7] Extension describes it as edible white flesh similar to dragon fruit, tasting like watermelon crossed with cantaloupe; ^[4] grower reports compare it to coconut-vanilla pudding and a mild creamy custard, ^[13][14] or melon with a lemon accent, and one grower who sampled a prepared fruit at a nursery found it bland and jelly-like. ^[12] The fruit is eaten primarily in Japan as a seasonal delicacy and is best fresh, after the pod has fully opened on the vine. ^[15] The seeds are hard and bitter and are generally not chewed — growers swallow them whole or spit them out, ^[13][14] and one reference cautions that chewing the seeds may irritate the throat. ^[15] The skin is bitter but edible cooked: in Japanese cooking the rind is fried, or stuffed with ground meat or mushrooms. ^[15] Young shoots are eaten as a cooked vegetable, leaves have served as a tea substitute, and the Chinese flora records the roots, stems and fruits as used medicinally. ^[7][8][2]

Cultivars and selections

The named selections are ornamental, chosen for flower color and foliage rather than fruit quality; no fruit-quality cultivar is documented in the references used here. ^[4] 'Silver Bells' (accepted RHS name) has white male flowers with purple-pink stamens and pinkish-purple female flowers, and, like the species, needs two plants and long, hot summers to fruit. ^[10] 'White Chocolate' (RHS Award of Garden Merit) is a vanilla-scented, white-to-pale-purple flowered selection whose fruit is recorded as whitish and banana-flavored; its name status is listed as unresolved, so it should be treated as a marketed selection rather than a formal cultivar. ^[11] Other names in the nursery trade include 'Alba' (white flowers), 'Rosea' (pink flowers), 'Shirobara' (white flowers), 'Compacta' (a less vigorous form) and 'Variegata' (variegated leaves with maroon-purple flowers). ^[4] White-flowered clones are commonly paired with the purple type for cross-pollination; bloom-time differences between the two can defeat the pairing. ^[14] For a fruit crop, request two genetically distinct plants rather than two cuttings of the same clone.

Photos

References

• ↑ [1] Akebia quinata — Plants of the World Online, Kew Science.

• ↑ [2] Akebia quinata (Houttuyn) Decaisne — Flora of China 6: 288–289, Lardizabalaceae treatment.

• ↑ [3] Wang, C.-H.; Zou, T.-T.; Liu, W.-Q.; Wang, X.-F. (2022). The influence of self-pollen deposition on female reproductive success in a self-incompatible plant, Akebia quinata. Frontiers in Plant Science 13: 935217.

• ↑ [4] Akebia quinata (Chocolate Vine, Five Leaf Akebia, Raisin Vine) — NC State Extension Plant Toolbox.

• ↑ [5] Akebia quinata — Plant Finder, Missouri Botanical Garden.

• ↑ [6] Akebia quinata (chocolate vine) — RHS Plant Profile.

• ↑ [7] Akebia quinata (five-leaf akebia) — CABI Compendium datasheet 3933.

• ↑ [8] Akebia quinata — Plants For A Future database.

• ↑ [9] Akebia — Plant of the Week, University of Arkansas Cooperative Extension Service.

• ↑ [10] Akebia quinata 'Silver Bells' (chocolate vine 'Silver Bells') — RHS Plant Profile.

• ↑ [11] Akebia quinata 'White Chocolate' (chocolate vine 'White Chocolate') — RHS Plant Profile.

• ↑ [12] Chocolate vines — Akebia trifoliata or Akebia quinata (Growing Fruit forum thread 8811).

• ↑ [13] Akebia — how long wait for fruit (Tropical Fruit Forum topic 43084).

• ↑ [14] My chocolate vine (Akebia quinata) fruited this year (Reddit r/GardeningUK).

• ↑ [15] Akebia quinata — Wikipedia.

Image credits

• File:Akebia quinata (vine, fruits, flowers) 01.jpg — Cultivated vine bearing foliage, flowers and fruits, trained on a fence in Port Coquitlam, BC, Canada (summary image). Creator: Ursus sapien (Wikimedia Commons), CC BY-SA 4.0 (license). File page: Wikimedia Commons. Attribution: Ursus sapien, CC BY-SA 4.0, via Wikimedia Commons.

• File:Akebia quinata leaf.jpg — Palmately compound leaves with five leaflets. Creator: monado (Japanese Wikipedia), CC BY-SA 2.5 (license). File page: Wikimedia Commons. Attribution: monado, CC BY-SA 2.5, via Wikimedia Commons.

• File:Akebia quinata (bud male).jpg — Male flower buds photographed at Mt Nōgōhaku, Motosu, Gifu Prefecture, Japan. Creator: Alpsdake (Wikimedia Commons), CC BY-SA 4.0 (license). File page: Wikimedia Commons. Attribution: Alpsdake, CC BY-SA 4.0, via Wikimedia Commons.

• File:Akebia quinata031.jpg — Immature fruit photographed in Nagano Prefecture, Japan. Creator: Apple2000 (Wikimedia Commons), CC BY-SA 3.0 (license). File page: Wikimedia Commons. Attribution: Apple2000, CC BY-SA 3.0, via Wikimedia Commons.

• File:Akebia quinata Kew Gardens.jpg — Vine growing on a wall at the Royal Botanic Gardens, Kew. Creator: LavaLampBamboo (Wikimedia Commons), CC BY-SA 4.0 (license). File page: Wikimedia Commons. Attribution: LavaLampBamboo, CC BY-SA 4.0, via Wikimedia Commons.