Family: Fabaceae Genus:Caragana Species:arborescens Common Names: Ross caragana, pea-tree, Siberian peatree, Siberian peashrub, common caragana Cultivars: Most of the current cultivars of common caragana are male. `Sutherland’ (narrow, upright form), `Lobergii’ (graceful form with fine textured leaves), `Pendula’ (stiffly weeping form with arching branches), `Walker’ (strongly weeping, fine textured leaves), `Nana’ (dwarf form with somewhat contorted branches), `Jefarb’ (seedless) (1).
Region of Origin Common caragana (Caragana arborescens) is native to Asia, particularly Siberia and Manchuria. It prefers well drained soils, but it will grow on very poor sites. In North America, it has been introduced to Canada and north of Nebraska in the United States. Its growth is stunted south of Nebraska (1). In Minnesota, the female common caragana plant is listed as an invasive species.
Fig. 1- Range of Caranga arborescens in the United States
Size at Maturity Common caragana is a deciduous small tree or shrub with a height of 10-15 feet with a spread of 12-15 feet (1). Leaves: Typically 3-5 inches long with 8-12 leaflets (1) that are .5-1 inches long (2). Flowers: Small, yellow pea-like flowers appearing in the spring (2). Fruit: Fruits are a cylindrical legume pod about 1.5-2 inches long. They start out green in the spring and early summer and turn tan in July and August (2).
Top Left: Fig.2- Leaves Top Right: Fig.3- Flowers Bottom Left: Fig. 4- Fruit Bottom Right: Fig. 5- Common caragana form
Life Expectancy Common caragana begins to bear fruit about 3-5 years after planting. Once it has been established, it can live for over 50 years (3).
Wood The wood of common caragana is ring porous (4). However, because it is a shrub or small tree, the wood doesn’t have any uses outside of firewood.
Site Characteristics USDA Plant Hardiness Zone: 2-7 (5). Soil: Common caragana will tolerate all types of soil textures. It also will tolerate a pH of between 5-8 (6). Moisture: Common caragana does best in well-drained soils, although it is very tolerant of poor sites (i.e. very dry soils, infertile soils) (1). Sun: Common caragana prefers full sun but will tolerate some shade (1). Growing Season: Common caragana requires a minimum of 150 frost free days to grow well (6).
Reproductive Details Common caragana is dioecious (separate male and female plants) with imperfect flowers (7). An imperfect flower is a flower that has either female or male parts, but not both. They are either wind or insect pollinated (3). The flowers tend to bloom in May and are done by June. The fruit is a legume, which is a pod with seeds inside. When the pods ripen, they break open, spreading the seeds (1). Common caragana can be propagated by cuttings, root cuttings, layering or grafting, as well as from seed. When propagated from seeds, the seeds should be soaked in warm water for 24 hours prior to being sown in a cold frame (1). A cold frame is a plastic or glass covered shelter that has no heat and is used to protected seedlings from the outdoors (8).
Uses Common caragana is mainly used as a hedge, shelterbelt or windbreak tree. It is a great nitrogen fixer, so it can be planted on sites where nothing else will grow (5). Furthermore, it has a deep, extensive root system, so it can be used for erosion control (3). The fruit of the common caragana is edible. Thus, it is a valuable source of food for wildlife. In the past, it has had some medicinal uses. It also produces fiber and dye (1). When planting common caragana, it is suggested to plant only the male, as it does not produce seed and is not invasive.
Fig.6-Common caraganaused as a windbreak
Maintenance Common caragana requires very little maintenance once it has been established (1).
Limitations Common caragana is not affected by any serious diseases or pests. It can withstand strong wind and extreme cold (up to -38 degrees Fahrenheit). It tolerates infertile soils, drought, alkaline soils and deicing salt (1).