Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
"During World War II, the Siberian peasants reportedly carried their chicken
flocks through the winter feeding the seed of one small woody pland,
Caragana arborescens." (Snell, 1983). Some ethnic groups have used
young pods for vegetables. Seeds serve as a valuable wild life food. Bark
provides a fiber. Leaves yield an azure dye. Because of its cold and drought
tolerance, it is widely planted in the US and Canada for windbreaks. In the
northern Great Plains, it is also used for hedges and outdoor screening.
Because of its nitrogen-fixing capacity, it is valued as a soil-improving
plant. In the Arctic Circle it is valued as a supplementary fodder for
reindeer herds. It is valuable in these colder climates, but in warmer
climates like New England as the eastern and western coastal areas of the US,
better ornamentals are available. According to Snell (1983), Caranga "serves
well as a windbreak, ground cover, soil builder, poultry cover, cattle forage,
vegetable for human use, fiber plant, bee plant, dye plant, and ornamental
According to the Dictionary of Chinese Traditional Medicine (Kiangsu, 1977),
the whole plant, known as ning tiao, is used for cancer of the breast, and the
orifice to the womb, and for dysmenorrhea and other gynecological problems.
According to USDA analyses, the ash content of the seed runs 3.4-3.6, protein
35.5-36.4%, oil content 13.2-13.6%. Contains a lectin or phytohemagglutinin.
Deciduous shrub or small tree 6-8 m tall; stipules becoming spiny, leaves
alternate, paripinnate, 5-9 cm long, with 3-6 pairs of obovate to
elliptic-oblong leaflets, to 2.5 cm long. Flowers yellowish, pea-shaped, one
to four in each cluster, the calyx teeth short, as broad as long. Fruit
stalked to 5 cm long, with 6 reddish-brown, oblong to spherical seeds, 2.5-4 0
mm in diam. (Seeds ca 40,000-42,000/kg).
Reported from the Eurosiberian Center of Diversity, Siberian peashrub is
reported to tolerate alkalinity, drought, cold, poor soil, and wind. Some
named variations are forma xorbergii, var. crasseaculeata, var.
nana, and var. pendula, the latter with handsome drooping
branches. (2n = 16)
Native to Siberia and Manchuria. Extends over about 160 million ha in Siberia
77deg.-120deg. E, 48deg.-60deg. N. In the US its growth is stunted south of
Apparently ranges from Cold Temperate Steppe to Moist through Boreal Moist to
Wet Forest Life Zones, Siberian peashrub tolerates annual precipitation of 4 to
8 dm, annual temperature of 2 to 7°C reaching Zone 2 (Hardiness Zone) of the
United States and Canada.
According to Hortus III (1976), pea trees grown for their flowers should be
planted in.sunny locations in sandy soil. Seeds are generally sown outdoors in
autumn, or in spring after soaking the seed in warm water. Softwood cuttings
can be set in early June. Also propagated by root cuttings, layering, or
grafting. Certain pesticides, captain, thiram, and mercuric chlorate can
increase germination, possibly by inhibiting disease. No significant
differences in characteristics of 1-year-old seedlings were noted following
Rhizobia inoculation of seeds prior to field sowing. However, one source
recommended inoculation for best results. Many nurserymen recommend planting
75-150 seeds per linear meter. A Russian report recommended planting 2.5 cm
deep. In one North Dakota nursery, Siberian peashrub is seeded during the last
week in July or the first week in August. A cover crop of oats is seeded
between the tree rows early enough to give winter protection. Shrubs are large
enough to dig the following fall (Ag Handbook 450).
In the US, the optimum time for collecting seed is less than two weeks, usually
in July or August. Since seeds are ready to collect as soon as the fruit
ripens, the pods should be gathered by hand as soon as they open. For
vegetable trials, greener pods should of course be harvested.
Shrubs take ca 3-5 years to reach commercial bearing age (Ag Handbook 450).
Good crops occur nearly every year.
With no data available, I speculate that this species could produce 4-10
MT/DM/yr fixing nitrogen in the process. Nitrogen-fixing rhizobia were
reported in the species before 1900. There is considerable variation in the 14
strains now reported, all belonging to the slow-growing cowpea-soybean-lupine
type rhizobia. Host infective patterns were quite uniform but some
nonreciprocal cross-inoculation was observed. Caragana rhizobia reisolated
from nodules they formed on Trifolium pratense retained the ability to
nodulate Caragana. Throughout the life of a Caragana nodule, the volume of
tissue functionally active in N-fixation remains more or less constant. As the
nodule becomes larger, the ratio of the N-fixing volume to total nodule mass
becomes smaller. On a one-month-old nodule, the ratio of functional
bacteroidal tissue to total nodule mass is about 1:1, in 2-month-olds, 1:2; in
6-month-olds 1:5. Of particular interest is the coexistence of juvenile and
senescent tissue in close proximity for long periods. Growth equilibrium,
development, and function of the nodule, do not appear unbalanced during its
existence (Allen and Allen, 1981).
Agriculture Handbook 165 lists: Agrobacterium rhizogenes (hairy root),
Ascochyta sp. (leaf blight), Botrytis cinerea (pod
blight), Cucurbitaria anae (on branches), Hendersonia
septem-septata (on twigs), Pellicularia filamentosa (root rot of
seedlings), Phomopsis caraganae and Phomopsis rudis (on
branches), Phyllosticta gallarum (leaf spot), Phymatotrichum
omnivorum (root rot), Phytophthora cactorum (wilt of seedlings),
Rhizoctonia solani (damping-off), Septoria sp. (leaf blight), and
Sphaeropsis sp. (on branches). Nursery stock may need pesticides to
prevent damage by spiders, blister beetles, and other leaf-eating insects.
Grasshoppers are especially destructive, sometimes completely defoliating the
plants. Plants have also been extensively damaged by browsing deer, but mammal
repellent has been effective (Ag Handbook 450).
Complete list of references for Duke, Handbook of Energy Crops
- Agriculture Handbook 165. 1960. Index of plant diseases in the United States.
Agriculture Handbook 450. 1974. Seeds of woody plants in the United States.
Forest Service, USDA. USGPO. Washington.
Allen, O.N. and Allen, E.K. 1981. The Leguminosae. The University of Wisconsin
Press. 812 p.
Hortus Third. 1976. A concise dictionary of plants cultivated in the United
States and Canada. MacMillan Publishing Co., Inc., New York.
Kiangsu - Institute of Modern Medicine. 1977. Encyclopedia of Chinese drugs. 2
Snell, T. 1983. Caragana: the pea shrubs. p. 41-44. In: The International
Permaculture Seed Yearbook 1983. Orange, MA.
Last update July 3, 1996