| Hosta | |
|---|---|
| Hosta Bressingham Blue, a Hosta cultivar | |
| Scientific classification | |
| Kingdom: | Plantae |
| clade: | Angiosperms |
| clade: | Monocots |
| Order: | Asparagales |
| Family: | Asparagaceae |
| Subfamily: | Agavoideae |
| Genus: | Hosta Tratt. |
| Species | |
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Hosta ( /ˈhɒstə/,[1] syn.: Funkia) is a genus of about 23–45 species of lily-like plants in the family Asparagaceae, subfamily Agavoideae,[2] native to northeast Asia. They have been placed in their own family, Hostaceae (or Funkiaceae); like many 'lilioid monocots', they were once classified in the Liliaceae. The scientific name is also used as the common name; in the past they were also sometimes called the Corfu Lily, the Day Lily, or the Plantain lily, but these terms are now obsolete. The name Hosta is in honor of the Austrian botanist Nicholas Thomas Host.[3] The Japanese name Giboshi is also used in English to a small extent. The rejected generic name Funkia, also used as a common name, can be found in some older literature.
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Hostas are herbaceous perennial plants, growing from rhizomes or stolons,[4] 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. Variation among the numerous cultivars is even greater, with clumps ranging from less than 4 in (10 cm) across and 3 in (8 cm) high to more than 6 ft (200 cm) across and 4 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, general 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 tepals, white, lavender, or violet in color and usually scentless. The only strongly fragrant species is Hosta plantaginea, which has white flowers up to 4 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. [5]Accordingly, the list of species at the right 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 Hosta formerly described as species taxonomically, have been reduced to cultivars; these often have their names conserved, and retain Latin names which resemble species names (e.g., H. 'Fortunei' ).
Though Hosta plantaginea originates in China, most of the species that provide the modern shade garden 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.
Hostas are widely cultivated ground cover plants, particularly useful in the garden as shade-tolerant plants. Hybridization within and among species and cultivars has produced numerous cultivars, with over 3000 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. Pictures of hosta species and cultivars, along with other information, may be found at http://www.hostalibrary.org.
The American Hosta Society and the British Hosta and Hemerocallis Society support Hosta Display Gardens, often within botanical gardens.
Hostas are edible by humans and are called "urui" in Japan where they are commonly consumed.[6] The parts eaten and the manner of preparation differ depending on the species; in some cases it is the shoots, others the leaf petiole, others the whole leaf. Younger parts are generally preferred as being more tender than older parts. The flowers are also edible. Descriptions (from a Western perspective) of the edibility of several species are at Plants for a Future.
Hostas are notoriously a favourite food for deer, slugs and snails, which commonly cause extensive damage to hosta collections in gardens. Poisoned baits using either metaldehyde or the safer iron phosphate work well for the latter, but require repeated applications. 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 little or no symptoms are seen. A potexvirus called Hosta Virus X has become common recently, and 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.
Otherwise they are generally easy and long-lived garden plants, relatively disease free, requiring little care other than watering and some fertilizer to enhance growth. Some varieties are more difficult to grow, as can be expected with 5,000+ cultivars, but most are easy enough for beginners.