Corethrodendron multijugum (Maxim.) B.H.Choi & H.Ohashi

TSO logo

Sponsor

Kindly sponsored by
a member of the International Dendrology Society

Credits

Julian Sutton (2023)

Recommended citation
Sutton, J. (2023), 'Corethrodendron multijugum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/corethrodendron/corethrodendron-multijugum/). Accessed 2024-03-28.

Synonyms

  • Hedysarum multijugum Maxim.

Other taxa in genus

    Glossary

    apex
    (pl. apices) Tip. apical At the apex.
    apiculate
    With a short sharp point.
    glabrous
    Lacking hairs smooth. glabrescent Becoming hairless.
    lax
    Loose or open.
    leaflet
    Leaf-like segment of a compound leaf.
    keel petal
    (in the flowers of some legumes) The two front petals fused together to form a keel-like structure.
    pollination
    Act of placing pollen on the stigma. Various agents may initiate pollination including animals and the wind.

    Credits

    Julian Sutton (2023)

    Recommended citation
    Sutton, J. (2023), 'Corethrodendron multijugum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/corethrodendron/corethrodendron-multijugum/). Accessed 2024-03-28.

    Small, multistemmed, deciduous shrub with erect stems to 70 cm (but sometimes well over 1 m in gardens). Stipules ovate-lanceolate, 4–6 mm, joined together at the base. Leaves 6–18 cm, with 15–29 broadly ovate to suborbicular leaflets, each 5–8(–15) × 3–5(–8) mm, hairy beneath. Inflorescence a lax, many-flowered raceme, the peduncle conspicuously longer than leaves. Pedicel 1–2 mm; bracteoles roughly equalling pedicel. Calyx obliquely campanulate, 5–6 mm, pubescent, the tube split to halfway between the upper teeth; teeth slender, tapering, the lowest about twice as long as others. Corolla purple, pinkish purple, or rarely white; banner broadly ovate, 1.7–2 cm; wings ~1/2 as long as standard; keel slightly shorter than wings. Ovary pubescent. Fruit usually divided into 2 or 3 ellipsoid to semiglobose sections, each 4 × 3–4 mm, pubescent and prickly. Flowering June–August (China), June–September (Britain); fruiting August–September (China). (Xu & Choi 2010; Bean 1981)

    Distribution  China Gansu, Hebei, W Henan, W Hubei, W Nei Mongol, Ningxia, Qinghai, Shaanxi, Shanxi, NW Sichuan, NE Xizang

    Habitat Gravelly areas, stony slopes; 500–3800 m asl.

    USDA Hardiness Zone 5-8

    RHS Hardiness Rating H6

    Conservation status Not evaluated (NE)

    Colour, rather than elegance of habit, is the main reason for growing this very hardy deciduous pea which suits well-drained soil in full sun. It is still widely known as Hedysarum multijugum in gardens.

    The flowers of the stock grown in Europe are a vivid shade of reddish purple, ‘objectionable to some people’ (Bean 1981), though desirable to others. They are carried in long, lax, but strongly upright racemes above the leaves; branches are freely produced, resulting in many inflorescences carried at the same level on the bush (Sprague 1906). It flowers over a long summer season, typically June to September in southern England. Such strong colours can be particularly cheering in the softer light of September. A small yellow patch at the base of each banner petal adds to the effect, as does the rather blue-green tint of the leaves. Thomas (1992) considered it an ‘acqusition of great value for certain colour-schemes, particularly for silvery-leafed plants and pale yellow or white flowers’. The typical peaflower structure suggests pollination by bees, although there have been no specific studies on this genus.

    Native to China’s semi-arid north, C. multijugum is adapted to a dry continental climate, with cold winters and hot summers. In our area there will be few places where winter cold poses a problem in itself, but wet soil is quite unsuitable. Vegetative growth may well be faster and looser in the lower light and higher rainfall of cool maritime climates such as Britain’s, perhaps explaining why cultivated plants may reach twice the height of wild ones. The resulting habit can attract adjectives such as sparse, gaunt, ungainly and lanky (Bean 1981; Thomas 1992). Bean (1981) suggests correcting this by pegging the branches down after a few years, causing them to break into new growth at the base.

    This species has been known and grown in Europe since the later 19th century. It was described scientifically in 1881 (as a Hedysarum) from specimens collected in Gansu by the Russian explorer Nikolay Przhevalsky. Maximovich’s specific epithet (from the Latin multi (many) and iugum (a yoke)) perhaps refers to its having more leaflets than the desert shrub C. fruticosum, to which it was compared. Plants were grown in St Petersburgh, Russia, from Przhevalsky’s seed collections, surviving winters in the open ground to flower in 1882 (Regel 1883). Plants growing at Kew, illustrated and described for Curtis’s Botanical Magazine (Sprague 1906), probably came from this source (Bean 1981) although no one can now be sure. It is entirely possible that everything we now grow derives from a single collection. Sprague (1906) described var. apiculatum from these Kew plants, supposedly differing from the type in the apiculate leaflet apex and the glabrous upper leaf surface. This name has stuck to cultivated plants (Cullen et al. 2011; Edwards & Marshall 2019) but it is not accepted by Flora of China (Xu & Choi 2010) or Plants of the World Online (Royal Botanic Gardens, Kew 2023), and is probably best ignored.

    In addition to seed (which is not always set), propagation is by layering or cuttings (Bean 1981).