Hardy Kiwi
Encyclopedia
Actinidia arguta is a perennial
vine
native to Korea
, Northern China
, and Russian Siberia
, producing a small fruit resembling the kiwifruit
.
The fruit are referred to as Hardy kiwifruit, kiwi berry, arctic kiwi, baby kiwi, dessert kiwi or cocktail kiwi and are edible, berry or grape-sized fruit similar to kiwifruit
in taste and appearance, but are green or purple with smooth skin. Often sweeter than the kiwifruit
, hardy kiwifruit can be eaten whole and need not be peeled. Thin-walled, its exterior is smooth and leathery.
The fast-growing, climbing vine
is very hardy (hence the name hardy kiwi), and is capable of surviving slow temperature drops to -34°C (-30°F), although young shoots can be vulnerable to frost in the spring. The vines need a frost-free growing season of about 150 days, but are not damaged by late freezes, provided that temperature changes are sufficiently gradual to allow plants to acclimate. Indeed, a period of winter chill is necessary for successful cultivation. However, rapid freezes will kill off buds and split vines. The vines can also be grown in low-chill areas.
In western Massachusetts and other isolated sites in New England, the vine has become quite invasive in forested areas. Forests provide a natural trellis for the vine to cling to as it grows vertically towards the sunlight. The weight of the winter snow on top of the hardy kiwi vine causes trees to collapse and fall. The vine spreads to new trees, causing them to collapse, creating a landscape which resembles an amphitheatre. Mammals and birds are able to spread hardy kiwi seeds to unwanted areas. The impact of hardy kiwi on New England's hardwood forests is unknown, as this is a newly discovered invasion.
While hardy kiwi may be grown directly from seeds (germination time is approximately one month), it is also possible to propagate from cuttings. Hardy kiwi cuttings may be grafted directly onto established kiwifruit
rootstock
, or rooted themselves. In domestic cultivation, a trellis may be used to encourage horizontal growth for easy maintenance and harvesting; however, vines grow extremely quickly and require a strong trellis for support. Each vine can grow up to 20 feet in a single season, given ideal growing conditions. For commercial planting, placement is important: plants can tolerate partial shade but yields will be optimized with full sunlight. Hardy kiwi vines consume large volumes of water; therefore, they are usually grown in well-drained acidic soils to prevent root rot.
For vines to bear fruit, both male and female plants must be present to enable pollination. A male pollinator can enable six female producers to fruit. Flowering typically occurs in May (in the Northern Hemisphere) starting in the third year of growth. If flowers become frost-burned, however, no fruit production will occur during the remainder of the year. An autumn harvest is standard among all varieties; within this, actual harvest times are highly dependent on local climate and the specific cultivar
grown. Each individual vine can produce up to 100 pounds of fruit per year, but average annual yield is approximately 50 pounds per vine. Both fruit size and total yield are highly cultivar-dependent. Fruits left to ripen on the vine contain a 18 to 25 percent sugar content at time of harvest.
Hardy kiwi vines are vulnerable to several botanical diseases, including phytophthora
crown and root rot (the most serious problem), botrytis
rot, and sclerotinia
blight
. Vines are also vulnerable to insect infestations, including root knot nematodes, two-spotted spider mites, leaf rollers, thrips
, and Japanese beetles. Cats can also pose a problem, as they are attracted to a catnip-like smell that is produced by the hardy kiwi vines. Cats have been known to destroy vines and dig up roots in search of the source of the scent.
Attempts to commercialize the fruit have been historically unsuccessful due to its short shelf-life and sporadic tendencies to ripen. However, attempts are being made to bring the fruit to greater bear, and commercial production initiatives are underway on a small scale in South America
, New Zealand
, Europe
, and the USA (in Oregon
, Washington, and northern New England
).
and Joseph Gerhard Zuccarini
in 1843 as Trochostigma argutum. It was then moved to the genus Actinidia in 1867 by Friedrich Anton Wilhelm Miquel
after the invalidly published suggestion by Jules Émile Planchon
to move the species.
The species consists of three varieties:
Actinidia arguta var. giraldii was originally described by Ludwig Diels
at the species rank (Actinidia giraldii) in 1905, but was later reduced to a variety of A. arguta in 1972 by Vladimir Nikolaevich Voroschilov. Actinidia arguta var. hypoleuca was originally described at the species rank (Actinidia hypoleuca) by Takenoshin Nakai
in 1904, but reduced to a variety of A. arguta in 1980 by Siro Kitamura.
Actinidia arguta had been placed in section
Leiocarpae and series
Lamellatae, but this current infrageneric classification is unsupported. A 2002 study of the nuclear DNA internal transcribed spacer
sequence and the plastid
matK gene sequence for cladistic analysis
revealed the current circumscription of the sections to be polyphyletic, with A. arguta forming a clade
with A. melanandra near the base of the phylogenetic
tree.
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
vine
Vine
A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...
native to Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
, Northern China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, and Russian Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
, producing a small fruit resembling the kiwifruit
Kiwifruit
The kiwifruit, often shortened to kiwi in many parts of the world, is the edible berry of a cultivar group of the woody vine Actinidia deliciosa and hybrids between this and other species in the genus Actinidia....
.
The fruit are referred to as Hardy kiwifruit, kiwi berry, arctic kiwi, baby kiwi, dessert kiwi or cocktail kiwi and are edible, berry or grape-sized fruit similar to kiwifruit
Kiwifruit
The kiwifruit, often shortened to kiwi in many parts of the world, is the edible berry of a cultivar group of the woody vine Actinidia deliciosa and hybrids between this and other species in the genus Actinidia....
in taste and appearance, but are green or purple with smooth skin. Often sweeter than the kiwifruit
Kiwifruit
The kiwifruit, often shortened to kiwi in many parts of the world, is the edible berry of a cultivar group of the woody vine Actinidia deliciosa and hybrids between this and other species in the genus Actinidia....
, hardy kiwifruit can be eaten whole and need not be peeled. Thin-walled, its exterior is smooth and leathery.
Cultivation
Vine
A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...
is very hardy (hence the name hardy kiwi), and is capable of surviving slow temperature drops to -34°C (-30°F), although young shoots can be vulnerable to frost in the spring. The vines need a frost-free growing season of about 150 days, but are not damaged by late freezes, provided that temperature changes are sufficiently gradual to allow plants to acclimate. Indeed, a period of winter chill is necessary for successful cultivation. However, rapid freezes will kill off buds and split vines. The vines can also be grown in low-chill areas.
In western Massachusetts and other isolated sites in New England, the vine has become quite invasive in forested areas. Forests provide a natural trellis for the vine to cling to as it grows vertically towards the sunlight. The weight of the winter snow on top of the hardy kiwi vine causes trees to collapse and fall. The vine spreads to new trees, causing them to collapse, creating a landscape which resembles an amphitheatre. Mammals and birds are able to spread hardy kiwi seeds to unwanted areas. The impact of hardy kiwi on New England's hardwood forests is unknown, as this is a newly discovered invasion.
While hardy kiwi may be grown directly from seeds (germination time is approximately one month), it is also possible to propagate from cuttings. Hardy kiwi cuttings may be grafted directly onto established kiwifruit
Kiwifruit
The kiwifruit, often shortened to kiwi in many parts of the world, is the edible berry of a cultivar group of the woody vine Actinidia deliciosa and hybrids between this and other species in the genus Actinidia....
rootstock
Rootstock
A rootstock is a plant, and sometimes just the stump, which already has an established, healthy root system, used for grafting a cutting or budding from another plant. The tree part being grafted onto the rootstock is usually called the scion...
, or rooted themselves. In domestic cultivation, a trellis may be used to encourage horizontal growth for easy maintenance and harvesting; however, vines grow extremely quickly and require a strong trellis for support. Each vine can grow up to 20 feet in a single season, given ideal growing conditions. For commercial planting, placement is important: plants can tolerate partial shade but yields will be optimized with full sunlight. Hardy kiwi vines consume large volumes of water; therefore, they are usually grown in well-drained acidic soils to prevent root rot.
For vines to bear fruit, both male and female plants must be present to enable pollination. A male pollinator can enable six female producers to fruit. Flowering typically occurs in May (in the Northern Hemisphere) starting in the third year of growth. If flowers become frost-burned, however, no fruit production will occur during the remainder of the year. An autumn harvest is standard among all varieties; within this, actual harvest times are highly dependent on local climate and the specific 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...
grown. Each individual vine can produce up to 100 pounds of fruit per year, but average annual yield is approximately 50 pounds per vine. Both fruit size and total yield are highly cultivar-dependent. Fruits left to ripen on the vine contain a 18 to 25 percent sugar content at time of harvest.
Hardy kiwi vines are vulnerable to several botanical diseases, including phytophthora
Phytophthora
Phytophthora is a genus of plant-damaging Oomycetes , whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural ecosystems. The genus was first described by Heinrich Anton de Bary in 1875...
crown and root rot (the most serious problem), botrytis
Botrytis
Botrytis may refer to:*Botrytis, the anamorphs of fungi of the genus Botryotinia**Botrytis cinerea, a mold important in wine making*Botrytis, the cauliflower cultivar group of Brassica oleracea...
rot, and sclerotinia
Sclerotinia
Sclerotinia is a genus of fungi in the family Sclerotiniaceae. The widely distributed species contains 14 species....
blight
Blight
Blight refers to a specific symptom affecting plants in response to infection by a pathogenic organism. It is simply a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. Accordingly, many diseases that primarily exhibit this...
. Vines are also vulnerable to insect infestations, including root knot nematodes, two-spotted spider mites, leaf rollers, thrips
Thrips
Thrips are tiny, slender insects with fringed wings . Other common names for thrips include thunderflies, thunderbugs, storm flies, thunderblights, and corn lice...
, and Japanese beetles. Cats can also pose a problem, as they are attracted to a catnip-like smell that is produced by the hardy kiwi vines. Cats have been known to destroy vines and dig up roots in search of the source of the scent.
Attempts to commercialize the fruit have been historically unsuccessful due to its short shelf-life and sporadic tendencies to ripen. However, attempts are being made to bring the fruit to greater bear, and commercial production initiatives are underway on a small scale in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, 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 the USA (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...
, Washington, and northern New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
).
Botanical history and taxonomy
Actinidia arguta was first described by Philipp Franz von SieboldPhilipp Franz von Siebold
Philipp Franz Balthasar von Siebold was a German physician and traveller. He was the first European to teach Western medicine in Japan...
and Joseph Gerhard Zuccarini
Joseph Gerhard Zuccarini
Joseph Gerhard Zuccarini was a German botanist, Professor of Botany at the University of München. He worked extensively with Philipp Franz von Siebold, assisting in describing his collections from Japan, but also described plants discovered in other areas, including Mexico.-References:...
in 1843 as Trochostigma argutum. It was then moved to the genus Actinidia in 1867 by Friedrich Anton Wilhelm Miquel
Friedrich Anton Wilhelm Miquel
Friedrich Anton Wilhelm Miquel was a Dutch botanist.He was head of the botanical gardens at Rotterdam , Amsterdam and Utrecht . He directed the Rijksherbarium at Leiden from 1862...
after the invalidly published suggestion by Jules Émile Planchon
Jules Émile Planchon
Jules Émile Planchon was a French botanist born in Ganges, Hérault.-Biography:After receiving his Doctorate of Science at the University of Montpellier in 1844, he worked for a while at the Royal Botanical Gardens in London, and for a few years was a teacher in Nancy and Ghent...
to move the species.
The species consists of three varieties:
- Actinidia arguta var. arguta (autonymAutonym (botany)In botanical nomenclature, autonyms are automatically created names, as regulated by the International Code of Botanical Nomenclature . Autonyms are cited without an author. Relevant provisions are in articles 6.8, 22.1-3 and 26.1-3....
) - Actinidia arguta var. giraldii (DielsLudwig DielsDr. Friedrich Ludwig Emil Diels , was a German botanist.Diels was born in Hamburg, the son of the classical scholar Hermann Alexander Diels. From 1900 to 1902 he traveled together with Ernst Pritzel through South Africa, Java, Australia and New Zealand. Shortly before the first world war he...
) Vorosch. - Actinidia arguta var. hypoleuca (NakaiTakenoshin Nakaiwas a Japanese botanist.-External links:* * * by Yong Shik Kim and Mike Maunder from CURTIS'S Botanical Magazine, Royal Botanic Gardens, Kew, UK. Vol. 15: 141-146, 1998....
) Kitam.
Actinidia arguta var. giraldii was originally described by Ludwig Diels
Ludwig Diels
Dr. Friedrich Ludwig Emil Diels , was a German botanist.Diels was born in Hamburg, the son of the classical scholar Hermann Alexander Diels. From 1900 to 1902 he traveled together with Ernst Pritzel through South Africa, Java, Australia and New Zealand. Shortly before the first world war he...
at the species rank (Actinidia giraldii) in 1905, but was later reduced to a variety of A. arguta in 1972 by Vladimir Nikolaevich Voroschilov. Actinidia arguta var. hypoleuca was originally described at the species rank (Actinidia hypoleuca) by Takenoshin Nakai
Takenoshin Nakai
was a Japanese botanist.-External links:* * * by Yong Shik Kim and Mike Maunder from CURTIS'S Botanical Magazine, Royal Botanic Gardens, Kew, UK. Vol. 15: 141-146, 1998....
in 1904, but reduced to a variety of A. arguta in 1980 by Siro Kitamura.
Actinidia arguta had been placed in section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...
Leiocarpae and series
Series (botany)
Series is a low-level taxonomic rank below that of section but above that of species.In botany, a series is a subdivision of a genus...
Lamellatae, but this current infrageneric classification is unsupported. A 2002 study of the nuclear DNA internal transcribed spacer
Internal transcribed spacer
ITS refers to a piece of non-functional RNA situated between structural ribosomal RNAs on a common precursor transcript. Read from 5' to 3', this polycistronic rRNA precursor transcript contains the 5' external transcribed sequence , 18S rRNA, ITS1, 5.8S rRNA, ITS2, 28S rRNA and finally the 3'ETS...
sequence and the plastid
Plastid
Plastids are major organelles found in the cells of plants and algae. Plastids are the site of manufacture and storage of important chemical compounds used by the cell...
matK gene sequence for cladistic analysis
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
revealed the current circumscription of the sections to be polyphyletic, with A. arguta forming a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
with A. melanandra near the base of the phylogenetic
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
tree.