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Caragana arborescens - Lam.

Siberian Pea Tree

Author	Lam.	Botanical references	11, 74, 200
Family	Leguminosae	Genus	Caragana
Synonyms
Known Hazards	Reports that this plant contains toxins have not been substantiated[65]. The occurrence of cystine in the seeds is doubtful[65].
Range	E. Asia - Siberia to Mongolia. Occasionally naturalized in Europe in France[50].
Habitat	River banks, pebbles, sands, open forests and forest edges, gully slopes and stony slopes[74].
Edibility Rating	5 (1-5)	Medicinal Rating	1 (1-5)

Physical Characteristics

A decidious Shrub growing to 6m by 4m at a fast rate.

The plant prefers light (sandy) and medium (loamy) soils, requires well-drained soil and can grow in nutritionally poor soil. The plant prefers acid, neutral and basic (alkaline) soils and can grow in very alkaline soil. It cannot grow in the shade. It requires dry or moist soil and can tolerate drought. The plant can tolerates strong winds but not maritime exposure.

Habitats

Woodland Garden; Sunny Edge; Hedge;

Edible Uses

Edible Parts: Seed; Seedpod.

Seed - cooked[2, 105]. Small but produced in abundance[11], there are 4 - 6 seeds per pod[202]. A bland flavour, it is best used in spicy dishes[183]. The raw seed has a mild pea-like flavour, though we are not sure if it should be eaten in quantity when raw[K]. The seed contains 12.4% of a fatty oil and up to 36% protein[183, 269], it has been recommended as an emergency food for humans[65]. More than just an emergency food, this species has the potential to become a staple crop in areas with continental climates[K]. Young pods - cooked and used as a vegetable[46, 61, 105, 177, 183, 269].

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Cancer; Emmenagogue.

The whole plant, known as ning tiao, is used in the treatment of cancer of the breast, and the orifice to the womb, and for dysmenorrhoea and other gynaecological problems[269].

Other Uses

Dye; Fibre; Hedge; Oil; Shelterbelt; Soil stabilization.

A fibre obtained from the bark is used for making cordage[46, 61, 74, 269]. A blue dye is obtained from the leaves[74, 269]. The seed contains 12.4% of a fatty oil[74]. The plant can be grown as a hedge[160]. It is quite wind-resistant and can also be planted in a shelterbelt[200]. The plant has an extensive root system and can be used for erosion control, especially on marginal land[160]. Because of its nitrogen-fixing capacity, it is valued as a soil-improving plant[269].

Cultivation details

Succeeds in most well-drained soils, preferring full sun and a light sandy dry or well-drained soil[1, 11, 200]. Tolerates very alkaline soils[202]. Plants do not require a rich soil[1, 11, 108], succeeding on marginal land[160]. Established plants are drought resistant[160]. Fast growing[188]. Dormant plants are hardy to about -30°c[184], they prefer a continental climate and do not grow so well in areas that do not have very cold winters[200]. They grow and fruit very well in the eastern half of the country, even in northern areas, though they do not do so well in the wetter west[K]. The young growth in spring, even on mature plants, is frost-tender and so it is best to grow the plants in a position sheltered from the early morning sun[K]. The Siberian pea shrub has an excellent potential to become a staple food crop. The seed is nutritious and wholesome, although rather small it is often very freely borne and is easily harvested[K]. This species has also been recommended as a nitrogen-fixing windbreak and ground cover plant that binds the soil and produces fibre and dye stuffs[218]. C. boisii and C. fruticosa are closely related to this species[182] and can probably be used similarly[K]. A very ornamental plant, some named forms have been developed for their ornamental value[182]. 'Nana' is a very compact dwarf form[183] that grows slowly[11]. 'Pendula' has stiffly pendent branches but is otherwise the same as the type species[11]. A good bee plant[74]. Plants in this genus are notably resistant to honey fungus[200]. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[200].

Propagation

Seed - best sown as soon as it is ripe in a cold frame[200]. It usually germinates in 2 weeks[K]. Stored seed should be pre-soaked for 24 hours in warm water then sown in a cold frame[78, 113, 200]. If the seed has not swollen then scarify it and re-soak for another 12 hours before sowing[138]. Germination usually takes place within 2 - 3 weeks at 20°c[138]. Good percentage[11]. As soon as they are large enough to handle, prick the seedlings out into individual pots and grow them on in a greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. There are approximately 40,000 seeds per kilo[269]. Cuttings of half-ripe wood, 7 - 10cm with a heel, July/August in a frame[113]. Layering in spring.

Cultivars

'Nana'

A very compact dwarf form[183] that grows slowly[11].

'Pendula'

A form with stiffly pendent branches, but otherwise the same as the type species[11].

Links

This plant is also mentioned in the following PFAF articles: Staple seed crops from perennials., Why Perennials, Woodland Garden Plants, Caragana arborescens - Pea Tree.

References

[K] Ken Fern
Notes from observations, tasting etc at Plants For A Future and on field trips.

[1] F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaces in 1992 by a new dictionary (see [200]).

[2] Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972 ISBN 0-486-20459-6
Lots of entries, quite a lot of information in most entries and references.

[11] Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981
A classic with a wealth of information on the plants, but poor on pictures.

[46] Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959
An excellent and very comprehensive guide but it only gives very short descriptions of the uses without any details of how to utilize the plants. Not for the casual reader.

[50] ? Flora Europaea Cambridge University Press 1964
An immense work in 6 volumes (including the index). The standard reference flora for europe, it is very terse though and with very little extra information. Not for the casual reader.

[61] Usher. G. A Dictionary of Plants Used by Man. Constable 1974 ISBN 0094579202
Forget the sexist title, this is one of the best books on the subject. Lists a very extensive range of useful plants from around the world with very brief details of the uses. Not for the casual reader.

[65] Frohne. D. and Pfänder. J. A Colour Atlas of Poisonous Plants. Wolfe 1984 ISBN 0723408394
Brilliant. Goes into technical details but in a very readable way. The best work on the subject that I've come across so far.

[74] Komarov. V. L. Flora of the USSR. Israel Program for Scientific Translation 1968
An immense (25 or more large volumes) and not yet completed translation of the Russian flora. Full of information on plant uses and habitats but heavy going for casual readers.

[78] Sheat. W. G. Propagation of Trees, Shrubs and Conifers. MacMillan and Co 1948
A bit dated but a good book on propagation techniques with specific details for a wide range of plants.

[105] Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976
The most comprehensive guide to edible plants I've come across. Only the briefest entry for each species, though, and some of the entries are more than a little dubious. Not for the casual reader.

[108] International Bee Research Association. Garden Plants Valuable to Bees. International Bee Research Association. 1981
The title says it all.

[113] Dirr. M. A. and Heuser. M. W. The Reference Manual of Woody Plant Propagation. Athens Ga. Varsity Press 1987 ISBN 0942375009
A very detailed book on propagating trees. Not for the casual reader.

[138] Bird. R. (Editor) Growing from Seed. Volume 3. Thompson and Morgan. 1989
Very readable magazine with lots of information on propagation.

[160] Natural Food Institute, Wonder Crops. 1987. 0
Fascinating reading, this is an annual publication. Some reports do seem somewhat exaggerated though.

[177] Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984 ISBN 3874292169
An excellent book for the dedicated. A comprehensive listing of latin names with a brief list of edible parts.

[182] Thomas. G. S. Ornamental Shrubs, Climbers and Bamboos. Murray 1992 ISBN 0-7195-5043-2
Contains a wide range of plants with a brief description, mainly of their ornamental value but also usually of cultivation details and varieties.

[183] Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990 ISBN 0-9628087-0-9
Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.

[184] Phillips. R. & Rix. M. Shrubs. Pan Books 1989 ISBN 0-330-30258-2
Excellent photographs and a terse description of 1900 species and cultivars.

[188] Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990 ISBN 0-86318-386-7
Excellent range of photographs, some cultivation details but very little information on plant uses.

[200] Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992 ISBN 0-333-47494-5
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.

[202] Davis. B. Climbers and Wall Shrubs. Viking. 1990 ISBN 0-670-82929-3
Contains information on 2,000 species and cultivars, giving details of cultivation requirements. The text is terse but informative.

[218] Duke. J. A. and Ayensu. E. S. Medicinal Plants of China Reference Publications, Inc. 1985 ISBN 0-917256-20-4
Details of over 1,200 medicinal plants of China and brief details of their uses. Often includes an analysis, or at least a list of constituents. Heavy going if you are not into the subject.

[269] Duke. J. Handbook of Energy Crops - 1983
Published only on the Internet, excellent information on a wide range of plants.

Readers Comments

Plants for a Future does not verify the accuracy of reader comments, use at your own risk. In particular Plants For A Future can not take any responsibility for any adverse effects from the use of plants. You should always consult a professional before using plants medicinally.

Caragana arborescens

Megan Mon Mar 27 2006

When I was about three years old in Victoria, B.C., I and two other small kids almost died from eating Cargana peapods. I remember them being pleasant to taste, not bitter. My parents had a very stressful time trying to awaken before my stomach was pumped. They only knew about it because one of the other children started throwing up and they went to the hospital. I was already in a deep sleep to which I would never have awoken except for them contacting my parents.

Caragana arborescens

Urban Fri Jun 2 2006

Are you sure it was caragana arborescens that you ate in Victoria? Not many growing around victoria, but lots of laburnum, scotch broom, etc; I have eaten caragana routinely, with no ill effect. It is most likely that you ate one of these.

Caragana arborescens

Erkki Aalto Sat Aug 19 2006

There is a beautiful tale about how Caragana arborescens came to Finland. I don't believe it is true, but let's record it here. When the Finnish POW:s returned to Finland after the Great Northern War they had Caragana seeds as food with them. At home they threw the remaining seeds away and the germinated. Anyway, Caragana grows well in Finland, which proves it is extremely tolerant.

Caragana arborescens

james finley Fri Jul 25 2008

I've never seen Caragana in Victoria but lots of Scotch Broom. Undoubtedly Megan ate the latter which is toxic Caragana thrives on the prairies but over time is a very invasive species like Scotch Broom. Yet it is highly drought tolerant, a great wind break and has wildlife value. The seed with their high energy and protein content do indeed have potential as a food and it is somewhat surprising that agricultural organizations have not looked into the development of cultivars. That being said, it is noteworthy that caragana peas do not seem to be consumed by native wildlife species suggesting that the raw seeds have some sort of alkaloidal deterrence mechanism. By the way, it is properly called the Siberian Peashrub, since it is not a tree.

Caragana arborescens

Thu Jun 11 2009

What would be the best way to remove or kill this tree completely?

Caragana arborescens

David Dildine Sun Jul 5 2009

I purchased a Caragana Arborescens a a nursery about June 1. It was about ten feet tall and shaped like a tree. It appeared healthy when I purchased it, but now a month later, the leaves are turning yellow, and the pods are brown and cracking. I may have over watered it. How much should it be watered, and if I did over water it, will it likely recover and survive?

Caragana arborescens

david (volunteer) Sun Jul 5 2009

David, I really cant say for sure, it may just be loosing its' leaves for the winter (if your'e in the southern hemisphere) it is drought tolerent (see Cultivation Details above) so shouldn't need much water,I'd give a generous water (a few minutes with a hose) once a week for a month or so to help it get established. In general the bigger the tree, ten feet would be big, the less adaptable it is to new situations, failure is more likely.

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