Horticulture/Clematis

Clematis is a genus of perennial plants, most of which are vigorous, semiwoody climbing vines, but others are herbaceous perennials or shrubs. They are found throughout the temperate regions of both hemispheres, and also in mountains in the tropics. Most of the cool temperate species are deciduous, while many of the warmer climate species are evergreen.

Most species are known as Clematis in English, while some are also known as traveller's joy, leather flower, vase vine and virgin's bower, the last three being names used for North American species.

One recent classification recognised 297 species of clematis and modern taxonomists subdivide the genus. Magnus Johnson divided Clematis into 19 sections, several with subsections; Christopher Grey-Wilson divided the genus into 9 subgenera, several with sections and subsections within them. Several of the subdivisions are fairly consistent between different classifications, for example all Grey-Wilson's subgenera are used as sections by Johnson.

Subgenera of Clematis according to Grey-Wilson:
 * Clematis, Cheiropsis, Flammula, Archiclematis, Campanella, Atragene, Tubulosae, Pseudanemone, Viorna

Some of these were previously classed as separate genera.

Description
Clematis have opposite (or in rare cases alternate), pinnately compound leaves, with the petioles often twining to support the plant. Flowers are borne solitary or in panicles, bell-shaped or flattened. Bisexual or sometimes unisexual, stamens many, carpels numerous. Sepals in 4s or 5s, petal-like, petals lacking. Stamens are petaloid in some species. Fruits are achenes, often with long, feathery styles. Stems contain an acrid sap, and the bark of wody species exfoliates in long strips.

Growing conditions
Deep, organic-rich soils. Most species need their root zones shaded during the growing season. Full sun to part shade.

Maintenance
Young shoots are very delicate in the spring and brittle afterwards, so trellis structures should be installed during winter.

Propagation
Stratified seed, layering, division, cuttings, or in rare cases grafting

Pests and diseases
../Crown Gall/ ../Powdery Mildew/ ../Leaf Spots/ ../Leaf Blights/ ../Wilts/ ../Mushroom Rots/ ../Rusts/ ../Smuts/ ../Nematodes/ ../Aphids/ ../Scales/
 * ../Agrobacterium tumeifasciens/
 * ../Erisiphe polygoni/
 * Cylindrosporium clematidis
 * Cercospora rubigo
 * Cercospora squalidula
 * Glomerella cingulata
 * Phyllosticta clematidis
 * Ramularia clematidis
 * Septoria clematidis
 * Phleospora adjusta
 * Ascochyta clematidina
 * ../Armillaria/
 * Puccinia pulsatillae
 * Puccinia recondita var. agropyri
 * Puccinia stromatica
 * Urocystis carcinoides
 * ../Meliodgyne hapla/
 * ../Meliodgyne incognita/
 * Green Peach Aphid: ../Myzus persicae/

../Whiteflies/

../Bugs/ ../Earwigs/
 * Garden Fleahopper: ../Halticus bractatus/

../Beetles/ ../Caterpillars/ ../Mites/
 * Black Blister Beetle: ../Epicuata pennsylvanica/
 * Japanese Weevil: ../Callirhopalus bifasciatus/
 * Clematis Borer: *../Alcathoe caudata/