Caragana arborescens, or Caragana or Siberian peashrub, is a species of legume. It is a perennial shrub or small tree growing to heights of 2?6 metres (6 ft 7 in?19 ft 8 in). The plant is native to Siberia and parts of China and neighboring Mongolia and Kazakhstan. It is commonly grown throughout the northern hemisphere as a landscaping plant and ornamental. Typically, it has a moderate to fast growth rate, being able to grow one to three feet during the first year after trimming.

Caragana has pod fruits which contain many seeds. These ripen in July and if left, will fall off the shrub and the seeds will grow to become a new plant very near the parent shrub. The leaves of the caragana vary from light green to dark green and are alternate and compound with many small leaflets. Somewhat showy, small, fragrant, yellow flowers bloom in spring[12].

Uses

Toxic parts

Reports that this plant contains toxins have not been substantiated[7]. The occurrence of cystine in the seeds is doubtful[7].

Edible uses

Seeds

Cooked, Fresh

The seeds can be cooked. [1][2] Small but produced in abundance[3], there are 4 - 6 seeds per pod[4]. A bland flavour, it is best used in spicy dishes[5]. The seed contains 12.4% of a fatty oil and up to 36% protein[5][6], it has been recommended as an emergency food for humans[7]. More than just an emergency food, this species has the potential to become a staple crop in areas with continental climates. The raw seed has a mild pea-like flavour, though it is not clear if it should be eaten in quantity when raw.

Seedpod

Cooked

Young pods can be cooked and used as a vegetable[8][9][2][10][5][6].

Flowers

Salad

The yellow flowers have a taste like peas and can be used in salads to add colour and some flavour.

Material uses

Leaves

Dye

A blue dye is obtained from the leaves[11][6].

Bark

Fibre

A fibre obtained from the bark is used for making cordage[8][9][11][6].

Seed

Oil

The seed contains 12.4% of a fatty oil[11].

Medicinal uses(Warning!)

Plant

Cancer

In Chinese medicine the whole plant, known as ning tiao, is used in the treatment of cancer of breast and cervical cancer, dysmenorrhoea and other gynaecological problems[6].

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[6].

Ecology

Ecosystem niche/layer

Secondary canopy or Shrub

Ecological Functions

Hedge

The plant can be grown as a hedge[13].

Windbreak

It is quite wind-resistant and can also be planted in a shelterbelt; it is extremely tough and has been used as windbreaks on the Canadian prairies[14][15]:252.

Earth stabiliser

The plant has an extensive root system and can be used for erosion control, especially on marginal land[13]

Nitrogen fixer

Because of its nitrogen-fixing capacity, it is valued as a soil-improving plant[6].

Ornamental

Somewhat showy, small, fragrant, yellow flowers bloom in spring. [12]

Forage

Chickens

The Siberian Pea Tree is oft cited as a good fodder plant to plan into a chicken run, orchard or field. If planted in with the chickens it drops good fodder straight into their foraging zone. The fruit is a pod which splits open when ripe, scattering the seed on the ground. The seed is released gradually over a number of months. In fact the chickens like the seed so much that they often can't wait for it to drop and do their best to fly up and pick it out of the pods[15]:252.

Bees

A very good bee plant[11]. The honey created has a pleasant taste, slightly 'fruity'[12].

Shelter

Nothing listed.

Propagation

The seed is not dormant but may require scarification. It can also be propogated by semi-ripe cuttings in summer or by layering in spring.

Seed

Seed - best sown as soon as it is ripe in a cold frame[14]. It usually germinates in 2 weeks[16]. Stored seed should be pre-soaked for 24 hours in warm water then sown in a cold frame[17][18][14]. If the seed has not swollen then scarify it and re-soak for another 12 hours before sowing[19]. Germination usually takes place within 2 - 3 weeks at 20°c[19]. Good percentage[3]. 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[6].

Rooted cuttings

Cuttings of half-ripe wood, 7 - 10cm with a heel, July/August [Britain] in a frame[18].

 

Cultivation

Succeeds in most well-drained soils, preferring full sun and a light sandy dry or well-drained soil[20][3][14]. Tolerates very alkaline soils[4]. Plants do not require a rich soil[20][3][21], succeeding on marginal land[13]. Established plants are drought resistant and fast growing [13][22]. Annual water requirement: 305mm - 1397mm[23]. Dormant plants are hardy to about -30°c[24], they prefer a continental climate and do not grow so well in areas that do not have very cold winters[14]. They grow and fruit very well in the eastern half of the England, even in northern areas, though they do not do so well in the wetter west[16]. 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.

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[16]. 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[25]. Caragana boisii and Caragana fruticosa are closely related to this species[26].

A very ornamental plant, some named forms have been developed for their ornamental value[26]. 'Nana' is a very compact dwarf form[5] that grows slowly[3]. 'Pendula' has stiffly pendent branches but is otherwise the same as the type species[3].

Plants in this genus are notably resistant to honey fungus[14]. 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[14].

  • Secondary canopy

  • Shrub

Functions

  • Hedge

  • Windbreak

  • Earth stabiliser

  • Nitrogen fixer

  • Ornamental

Light

  • Full sun

  • no shade

Water

  • Water Requirementsmoderate

Soil

  • acid, neutral, alkaline, very alkaline

Additional information for Siberian Pea Shrub

 2 pictures - click to enlarge

 Related

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Nitrogen fixing plant species suited to temperate climate such as North Canterbury New Zealand

Nitrogen fixing plant species suited to temperate climate such as North Canterbury New Zealand

Nitrogen is an essential element for plant growth. Certain plants have a useful ability to capture nitrogen from the atmosphere. This is often achieved through symbiotic relationship with fungi in the root zone. Being able access unlimited nitrogen allows these plants to grow quickly while also making some available to surrounding plants. The practical reality is that including nitrogen fixing plants of various shapes and sizes amongst other productive plantings improves overall health, vigour and fertility,