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Clematis

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For the township in Australia, see Clematis, Victoria. For the film, see Traveller's Joy.


Clematis
Clematis 'Nelly Moser'
Scientific classification
Kingdom:
Plantae
(unranked):
Angiosperms
(unranked):
Eudicots
Order:
Ranunculales
Family:
Ranunculaceae
Subfamily:
Ranunculoideae
Tribe:
Anemoneae
Genus:
Clematis

Species

See text.

Synonyms

Atragene L.
Coriflora Weber
Viorna Rchb.[1]

Clematis (KLEma-tis)[2] is a genus of about 300 species[3] within the buttercup family Ranunculaceae. Their garden hybrids have been popular among gardeners,[4] beginning with Clematis × jackmanii, a garden standby since 1862; more hybrid cultivars are being produced constantly. They are mainly of Chinese and Japanese origin. Most species are known as clematis in English, while some are also known as traveller's joy a name invented for the sole British native, C. vitalba by the herbalist John Gerard, virgin's bower for C. viticella, old man's beard, applied to several with prominent seedheads, leather flower or vase vine for the North American Clematis viorna.

Etymology

The genus name is from Ancient Greek clématis, a climbing plant, most probably a periwinkle. There are approximately over two hundred and fifty species and cultivars, often named for their originators or particular characteristics.

Botany

The genus is composed of mostly vigorous, woody, climbing vines / lianas. The woody stems are quite fragile until several years old.[4] Leaves are opposite and divided into leaflets and leafstalks that twist and curl around supporting structures to anchor the plant as it climbs.[4] Some species are shrubby, while others, like C. recta, are herbaceous perennial plants. The cool temperate species are deciduous, but many of the warmer climate species are evergreen. They grow best cool, moist, well-drained soil in full sun.[5]

Clematis species are mainly found throughout the temperate regions of the northern hemisphere, rarely in the tropics. Clematis leaves are food for the caterpillars of some Lepidoptera species, including the Willow Beauty (Peribatodes rhomboidaria).

The timing and location of flowers varies; spring-blooming clematis flower on side shoots of the previous year's stems, summer/fall blooming clematis bloom only on the ends of new stems, and twice-flowering clematis do both.[4]

Garden history

The wild Clematis species native to China made their way into Japanese gardens by the 17th century. Japanese garden selections were the first exotic clematises to reach European gardens, in the 18th century, long before the Chinese species were identified in their native haunts at the end of the 19th century.[6]

Use and toxicity

The European species did not enter into the herbalists' pharmacopeia[7] In the American Old West the Western white clematis, Clematis ligusticifolia, was called pepper vine by early travelers and pioneers of the American Old West, who took a tip from Spanish colonials and used seeds and the acrid leaves of yerba de chivato as a pepper substitute.[8] The entire genus contains essential oils and compounds which are extremely irritating to the skin and mucous membranes. Unlike black pepper or Capsicum, however, the compounds in clematis cause internal bleeding of the digestive tract if ingested in large amounts. C. ligusticifolia is essentially toxic. When pruning them, it's a good idea to wear gloves. Despite its toxicity, Native Americans used very small amounts of clematis as an effective treatment for migraine headaches and nervous disorders. It was also used as an effective treatment of skin infections.[9] Clematis is also a constituent of Bach's Rescue Remedy.

Pests and diseases

Clematis are susceptible to several pests and diseases. Clematis wilt, a stem rot caused by the fungus Phoma clematidina, causes dramatic wilting and death of whole branches, although many species are resistant to it.[10] Other pests and diseases include powdery mildew, viruses, slugs and snails, scale insects, aphids, earwigs and "green flower disease" (usually caused by infection with a phytoplasma).[11]

Species

Purple clematis
Clematis montana
Flowers of Clematis vitalba
Seed heads of Clematis vitalba growing in a hedge, showing why it is known colloquially as "Old man's beard"
Closeup of a Clematis flower, cultivar 'Multi Blue'
Achenes

A partial list of species:

Formerly placed here

Subdivisions

One recent classification recognised 297 species of clematis, so it is not surprising that taxonomists and gardeners subdivide the genus. Several classification systems exist.

Magnus Johnson divided Clematis into 19 sections, several with subsections.[15] Christopher Grey-Wilson divided the genus into 9 subgenera (Clematis, Cheiropsis, Flammula, Archiclematis, Campanella, Atragene, Tubulosae, Pseudanemone, Viorna), several with sections and subsections within them.[16] Several of the subdivisions are fairly consistent between these two systems; for example, all of Grey-Wilson's subgenera are used as sections by Johnson. Alternatively, John Howell defined twelve groups: the Evergreen, Alpina, Macropetala, Montana, Rockery, Early Large-Flowered, Late Large-Flowered, Herbaceous, Viticella, Texensis, Orientalis, and Late Mixed groups.[17]

Many of the most popular garden forms are cultivars belonging to the Viticella section of the subgenus Flammula as defined by Grey-Wilson. These larger-flowered cultivars are often used within garden designs to climb archways, pergolas, wall-mounted trellis or to grow through companion plants. These forms normally have large 12–15 cm diameter upward-facing flowers and are believed to involve crosses of C. patens, C. lanuginosa and C. viticella.[18] Early-season, large-flowering forms (e.g. "Nelly Moser") tend towards the natural flowering habit of C. patens or C. lanuginosa while later-flowering forms (e.g. x jackmanii) are nearer in habit to C. viticella.

References

  1. ^ a b "Genus: Clematis L." Germplasm Resources Information Network. United States Department of Agriculture. 2000-12-20. Retrieved 2011-02-02.
  2. ^ Sunset Western Garden Book. 1995. pp. 606–7.
  3. ^ There are more wild species of clematis even than of roses", Alice M. Coats remarks in Garden Shrubs and Their Histories (1964) 1992, s.v. "Clematis".
  4. ^ a b c d Bender, Steve, ed. (2004). "Clematis". The Southern Living Garden Book (2nd ed.). Birmingham, Alabama: Oxmoor House. pp. 250–2. ISBN 0-376-03910-8. {{cite encyclopedia}}: Unknown parameter |month= ignored (help)
  5. ^ Hillier Nurseries, The Hillier Manual of Trees and Shrubs, David and Charles, 1998, p723 ISBN 0 7153 0808 4
  6. ^ Coats (1964) 1992.
  7. ^ Of the native European C.vitalba Alice Coats observes "The leaves are acrid and poisonous, and not even the early herbalists attempted to use the plant in internal medicine", but she notes that John Gerard called Clematis flammula Biting Clematis or Purging Periwinkle. (Coats 1992).
  8. ^ US Native Plant Database Clematis ligusticifolia
  9. ^ Tilford, Gregory L. Edible and Medicinal Plants of the West. ISBN 0-87842-359-1.
  10. ^ Howells, J., Choosing your Clematis, Garden Art Press, 2003, pp115-116 ISBN 1 870673 47 6
  11. ^ Buczacki, S. and Harris, K., Pests, Diseases and Disorders of Garden Plants, HarperCollins, 1998, p65 ISBN 0 00 220063 5
  12. ^ Clematis ternifolia, Annie's Annuals.
  13. ^ a b "GRIN Species Records of Clematis". Germplasm Resources Information Network. United States Department of Agriculture. Retrieved 2011-02-02.
  14. ^ "Clematis". Integrated Taxonomic Information System. Retrieved 2011-02-02.
  15. ^ Johnson, Magnus (2001). The Genus Clematis. Magnus Johnson Plantskola AB.
  16. ^ Grey-Wilson, Christopher (2000). Clematis: The Genus: A Comprehensive Guide for Gardeners, Horticulturists and Botanists. Timber Press.
  17. ^ Howell's 12 Groups
  18. ^ Evison, Raymond J. (1998). The Gardener's Guide to Growing Clematis. Timber Press/David and Charles.

Further reading

Wikimedia Commons has media related to Clematis.
Wikispecies has information related to Clematis.
Wikisource has the text of the 1911 Encyclopædia Britannica article "Clematis".
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