|Hosta Bressingham Blue, a Hosta cultivar|
Tratt. 1817, conserved name, not Jacq. 1797 (syn of Cornutia in Lamiaceae) nor Vell. ex Pfeiff. 1874 (Primulaceae)
Hosta (//, syn. Funkia) is a genus of plants commonly known as hostas, plantain lilies (particularly in Britain) and occasionally by the Japanese name giboshi. Hostas are widely cultivated as shade-tolerant foliage plants. The genus is currently placed in the family Asparagaceae, subfamily Agavoideae, and is native to northeast Asia (China, Japan, Korea, and the Russian Far East). Like many "lilioid monocots", the genus was once classified in the Liliaceae. The genus was named by Austrian botanist Leopold Trattinnick in 1812, in honor of the Austrian botanist Nicholas Thomas Host. In 1817, the generic name Funkia was used by German botanist Kurt Sprengel in honor of Heinrich Funk, a collector of ferns and alpines; this was later used as a common name and can be found in some older literature.
Hostas are herbaceous perennial plants, growing from rhizomes or stolons, with broad lanceolate or ovate leaves varying widely in size by species from 1–18 in (3–45 cm) long and 0.75–12 in (2–30 cm) broad. The smallest varieties are called miniatures. Variation among the numerous cultivars is even greater, with clumps ranging from less than four in (10 cm) across and three in (8 cm) high to more than six ft (200 cm) across and four ft (130 cm) high. Leaf color in wild species is typically green, although some species (e.g., H. sieboldiana) are known for a glaucous waxy leaf coating that gives a blue appearance to the leaf. Some species have a glaucous white coating covering the underside of the leaves. Natural mutations of native species are known with yellow-green ("gold") colored leaves or with leaf variegation (either white/cream or yellowish edges or centers). Variegated plants very often give rise to sports that are the result of the reshuffling of cell layers during bud formation, producing foliage with mixed pigment sections. In seedlings variegation is generally maternally derived by chloroplast transfer and is not a genetically inheritable trait.
The flowers are produced on erect scapes, generally taller than the leaf mound, that end in terminal racemes. The individual flowers are usually pendulous, 0.75–2 in (2–5 cm) long, with six petals, white, lavender, or violet in color and usually scentless. The only strongly fragrant species is Hosta plantaginea, which has white flowers up to four in (10 cm) long; it is also unusual in that the flowers open in the evening and close by morning. This species blooms in late summer and is sometimes known as "August Lily".
Taxonomists differ on the number of Hosta species; there may be as many as 45. Accordingly, the list of species given here may be taken loosely. The genus may be broadly divided into three subgenera. Interspecific hybridization occurs since all the species have the same chromosome number (2n = 2x = 60); except H. ventricosa which is a natural tetraploid that sets seed through apomixis. Many cultivated hostas formerly described as species have been reduced to cultivars; these often have their names conserved, and retain Latin names which resemble species names (e.g., H. 'Fortunei').
- accepted species
as of October 2014
- Hosta albofarinosa - Anhui
- Hosta × alismifolia - Honshu
- Hosta capitata - Japan, Korea
- Hosta clausa - Korea, Manchuria, Primorye
- Hosta gracillima - Shikoku
- Hosta hypoleuca - Honshu
- Hosta jonesii - Korean Islands
- Hosta kikutii - Japan
- Hosta kiyosumiensis - Honshu
- Hosta longipes - Japan, Korea
- Hosta longissima - Japan, Korea
- Hosta minor - Kyushu, Korea
- Hosta plantaginea - China
- Hosta pulchella - Kyushu
- Hosta pycnophylla - Honshu
- Hosta rectifolia - Sakhalin, Kuril, Japan
- Hosta rupifraga - Hachijo-jima
- Hosta shikokiana - Shikoku
- Hosta sieboldiana - Japan, Korea
- Hosta sieboldii - Japan
- Hosta tsushimensis - Kyushu
- Hosta ventricosa - S China
- Hosta venusta - Jeju-do, Japan
- Hosta yingeri - Korean Islands
Hostas are widely cultivated, being particularly useful in the garden as shade-tolerant plants whose striking foliage provides a focal point. Though Hosta plantaginea originates in China, most of the species that provide the modern plants were introduced from Japan to Europe by Philipp Franz von Siebold in the mid-19th century. Newer species have been discovered on the Korean peninsula as well. Hybridization within and among species and cultivars has produced numerous cultivars, with over 3,000 registered and named varieties, and perhaps as many more that are not yet registered with the American Hosta Society. Cultivars with golden- or white-variegated leaves are especially prized. Popular cultivars include 'Francee' (green leaves with white edges), 'Gold Standard' (yellow leaves with green edges, discovered by Pauline Banyai) 'Undulata' (green leaves with white centers), 'June' (blue-green leaves with creamy centers), and 'Sum and Substance' (a huge plant with chartreuse-yellow leaves). Newer, fragrant cultivars such as 'Guacamole' are also popular.
The American Hosta Society and the British Hosta and Hemerocallis Society support Hosta Display Gardens, often within botanical gardens. Hostas are frequently exhibited at major shows such as the Chelsea Flower Show.
Pests and diseases
Hostas are eaten by deer, rabbits, voles, slugs and snails, which can cause extensive damage to collections in gardens. Some varieties seem more resistant to slug damage than others. Poisoned baits using either metaldehyde or the safer iron phosphate work well, but require repeated applications (and may be more toxic to other creatures despite claims to the contrary). Deer control tends to be variable, as anything other than fencing tends to work for a few years then ceases to work as they become accustomed to it.
Foliar nematodes, which leave streaks of dead tissue between veins, have become an increasing problem since changes in attitudes about pesticides since the mid-1990s in many countries have caused a resurgence in this once-controlled pest. There are no effective means for eliminating nematodes in the garden, although they can be controlled to the point where few or no symptoms are seen.
A potexvirus called 'Hosta Virus X' was first identified in Minnesota, USA in 1996. Plants that are infected must be destroyed as the disease can be transmitted from plant to plant by contaminated sap. Symptoms include dark green "ink bleed" marks in the veins of yellow-colored leaves, and/or tissue collapse between veins. It can take years for symptoms to show, so symptomless plants in infected batches should also be considered infected. 
- Tropicos, search for Hosta
- Tropicos, search for Saussurea
- Tropicos, search for Libertia
- Kew World Checklist of Selected Plant Families
- Sunset Western Garden Book, 1995:606–607
- Stevens, P.F., Angiosperm Phylogeny Website: Asparagales: Agavoideae
- Diana Wells 100 Flowers and How They Got Their Names, p. 96, at Google Books
- Mikolajski, A. (1997). Hostas - The New Plant Library, Canada: Lorenz Books. ISBN 1-85967-388-0
- "Hostas - taxonomy". hostas.fr. Retrieved 24 March 2015.
- "RHS Plant Selector - Hosta 'Aureomarginata' (ventricosa)". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta 'Blue Angel' (sieboldiana)". Retrieved 5 August 2015.
- "RHS Plant Selector - Hosta' 'Francee' (fortunei)". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta 'Frances Williams' (sieboldiana)". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta 'Golden Tiara'". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta (Tardiana Group) 'Halcyon'". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta fortunei var. aureomarginata". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta plantaginea var. japonica". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta sieboldiana var. elegans". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta undulata var. undulata". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta ventricosa". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta venusta". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta (Tardiana Group) 'June'". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta 'Krosse Regal'". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta 'Royal Standard'". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta 'Sagae'". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta 'Sum and Substance'". Retrieved 22 June 2013.
- "RHS Plant Selector - Hosta 'Wide Brim'". Retrieved 22 June 2013.
- "Hosta". American Society for the Prevention of Cruelty to Animals. Retrieved 9 July 2014.
- "Hosta virus X (Potexvirus)". eppo.int (European and Mediterranean Plant Protection Organization). Retrieved 5 August 2015.
- Lewandowski, Dennis J. (2008). "Hosta Virus X" (PDF). The Ohio State University. pp. 1–3. Retrieved 5 August 2015.
|Wikimedia Commons has media related to Hosta.|
- American Hosta Society
- Hosta Library 17000 Hosta Photographs, Articles, and Hosta Auction
- Hosta Virus X, Kansas State University
- HOSTAS Cubit (ID, Hybridizing, Sources databases; forums)
- Danish Hosta Society
- Plants for a Future Descriptions (from a Western perspective) of the edibility of several species
- Hosta Lists and Hosta Garden Themes Don Rawson's Hosta Lists, containing over 16000 entries in 86 lists.