Clematis

Japanese: クレマチス - くれまちす

A general term for the genus Clematis in the Ranunculaceae family (APG classification: Ranunculaceae). Evergreen or deciduous climbing plants (vines) with thin stems and curved petioles that twine around other objects. Leaves are generally compound leaves consisting of 3-9 leaflets. Flowers have 4-8 petal-like perianths, numerous stamens, and pistils consisting of numerous free carpels. The fruit is an achene, with a feathery style at the end that elongates after flowering. They are widely distributed from the tropics to the subarctic, mainly in the temperate zones of the world, with around 300 known species. In Japan, there are 25 species, including the Japanese quince, the Japanese grass button, the Clematis globosa, and the Japanese quince.

In horticulture, plants known as clematis include C. lanuginosa Lindl. (wisteria-colored eight-petal flowers). C. florida Thumb. has white six-petal flowers with many stamens in the center. C. patens Moor. et Decne. is a polyfloral plant with eight white, wisteria and purple petals. C. viticella L. has purple four-petal flowers. C. integrifolia L. has pale purple, four-petaled florets. Many cultivars have been developed in Europe by crossbreeding these several species, and breeding efforts are currently underway in various countries.

The main horticultural varieties include the purple varieties The President, White Crown, and Edo Murasaki, as well as the blue varieties Fujimusume and Lazar Stern, the red varieties Crimson King, the pink varieties Comtesse de Beauchard, and the original species of the cover and yellow varieties Tanguchika. These varieties are grown by twining around supports, but in recent years, semi-climbing varieties that do not require supports and are suitable for potted plants (such as "Tateshina") have been developed.

[Katsumi Kaneko March 18, 2020]

Cultivation

It can be propagated by cuttings or grafting, but in recent years it is mostly propagated by cuttings. The best time to take cuttings is June to August. Cut the new shoots that grow after flowering at 2-3 nodes and insert them into Kanuma soil, peat moss, or perlite. The optimum temperature for growth is 20-25°C, and it is particularly vulnerable to high summer temperatures, so it should be grown in a well-ventilated location in partial shade out of the western sun. For potted plants, it is best to let it spend the summer in the shade of a well-ventilated tree. It is very cold-resistant, and it easily survives winter. The best soil to use is fertile, rich in organic matter, has good water retention and good drainage. It grows well when grown with lots of fertilizer. After flowering, pick off the dead flowers and cut the branches slightly to allow new shoots to appear and produce good flowers.

Clematis is vulnerable to nematodes, which can impair growth and even cause the plant to die, so be sure to disinfect it with a nematode killer before planting. Also, keep the plant away from high temperatures, as damping-off disease is more likely to occur during these periods.

[Katsumi Kaneko March 18, 2020]

Cultural history

Tessen is native to China and was introduced to Japan by the late 15th century. It appears in the Muromachi period Kurohon Setsuyoshu and Bunmeihon Setsuyoshu under the name Tessenka. Kazaguruma is native to Japan and saw differentiation of varieties during the Genroku period, with white, light purple, lapis lazuli and double-flowered varieties recorded in Kadanchikinsho (1695). Tessen was introduced to Europe by Siebold in the early 19th century. Then in the 1830s, cross-breeding was started by Henderson in England, leading to improved varieties.

[Hiroshi Yuasa March 18, 2020]

Tessen
A typical type of clematis. The flowers have no petals, and the filaments of the numerous stamens are flat and dark purple. There are six white sepals that are petal-like. ©Seishohmaru ">

Tessen

Clematis (White Crown)
A purple cultivar. There are about 250 known species of clematis, and many cultivars are the result of complex hybridization. ©Shogakukan ">

Clematis (White Crown)

Grass button
From August to October, numerous flowers grow downward on large panicles. They are thin and bell-shaped, with the tips of the four sepals curling back. ©Seishohmaru ">

Grass button

Clematis
It is commonly found in sunny forest edges in the mountains and fields. From August to September, it produces large panicles and many white flowers. It has no petals, and the four sepals open flat. ©Shogakukan Photo by Okuyama Hisashi ">

Clematis

Mountain Crane
The leaves are compound, twice trifoliate, and the leaflets have rough sawtooth. From June to August, the triangular, bell-shaped, reddish purple flowers bloom one by one, facing downwards. ©Shogakukan Photo by Fujio Aoyama ">

Mountain Crane

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

キンポウゲ科（APG分類：キンポウゲ科）センニンソウ属の総称。常緑または落葉性の藤本(とうほん)（つる植物）で、茎は細く、葉柄が曲がって他物に絡みつく。葉は一般に3～9枚の小葉からなる複葉。花は4～8枚の花弁状の花被(かひ)、多数の雄しべ、多数の離生心皮からなる雌しべがある。果実は痩果(そうか)で、先に花期後伸長した羽毛状の花柱がある。世界の温帯を中心に熱帯から亜寒帯に広く分布し、300種ほど知られる。日本にはカザグルマ、クサボタン、センニンソウ、ハンショウヅルなど25種が分布する。

　園芸上でクレマチスといわれるものにC. lanuginosa Lindl.（藤(ふじ)色の8弁花）などがある。テッセンC. florida Thumb.は白色の6弁花で中央に多数の雄しべがある。カザグルマC. patens Moor. et Decne.は白、藤、紫色の8弁花で多花性。C. viticella L.は紫色の4弁花。キダチテッセンC. integrifolia L.は淡紫色で4弁の小花をつける。これら数種類の交雑によって多くの品種がヨーロッパで作出され、現在は各国で品種改良が進められている。

　おもな園芸品種としては、紫色系のザ・プレジデント、白王冠、江戸紫などのほか、青色系の藤娘、ラザー・スターン、紅色系のクリムソン・キング、桃色系のコンテス・ド・ボシャール、覆色系や黄色系の原種であるタングチカなどがある。これらの品種は支柱に絡ませてつくるが、近年は支柱のいらない半つる性で鉢植えに適した品種（「たてしな」など）もつくられている。

［金子勝巳　2020年3月18日］

栽培

繁殖は挿木、接木(つぎき)とも可能であるが、近年はほとんど挿木で殖やす。挿木の適期は6～8月で、開花後に伸びた新梢(しんしょう)を2～3節のところで切り、鹿沼土(かぬまつち)や「ピートモス」「パーライト」などに挿す。生育適温は20～25℃で、夏の高温にはとくに弱いので西日の当たらない半日陰で風通しのよいところで育てる。鉢植えは風通しのよい木陰で夏を越させるとよい。耐寒性は非常に強く、冬越しは容易である。用土は、有機質に富んだ肥沃(ひよく)で保水力が強く排水のよいものがよい。多肥栽培でよく成長する。花期後は花がらを摘み取り、枝をやや切り詰めると新梢が発生し、よい花をつける。

　クレマチスはネマトーダ（線虫類）の被害に弱く、生育が害され枯死することもあるので、定植前にかならず殺ネマトーダ剤で消毒する。また高温期には立枯病が多発生しやすいので、高温に当てないようにする。

［金子勝巳　2020年3月18日］

文化史

テッセンは中国原産で、日本へは15世紀後半までに渡来していた。室町時代の『黒本節用集(くろほんせつようしゅう)』や『文明本(ぶんめいほん)節用集』に鉄線花の名で載る。カザグルマは日本原産で、元禄(げんろく)時代には品種分化がみられ、『花壇地錦抄(かだんちきんしょう)』（1695）に白、薄紫、瑠璃(るり)色と八重咲きが記録されている。ヨーロッパには、19世紀の初めにシーボルトがテッセンを伝えた。また1830年代に、イギリスのヘンダーソンによって交雑育種が開始され、品種改良が進んだ。

［湯浅浩史　2020年3月18日］