|Official Plant Name||Caragana arborescens|
|Common Name(s)||Siberian Pea Tree, Siberian Pea Shrub|
|Plant Type||Tree / Shrub|
|Native Area||Siberia / Manchuria|
|Flowers||Pale yellow flowers, followed by pods|
|When To Plant||January, February, March, November, December|
|Flowering Months||June, July|
|Harvesting Months||September, October|
Sheltered or Exposed
4 – 8M
2.5 – 4M
May – July
Well-drained or moist but well-drained
Caragana plants are a top choice when you have no time, poor soils, exposed locations, hard freezes, and other circs that most plants cannot tolerate.
But though it’s as tough as nails, Caragana is not some scrub – it has brilliant green foliage, merry yellow blooms, and offers up tasty peas in autumn. And it can be grown as a large shrub, screening hedge, or small tree!
Shrub or Tree?
Tall shrub or small tree?
If the question and the horticultural game behind it interests you, you can’t go wrong with Caragana. This is a genus of about 90 species, the vast majority of which are shrubs and only a few are small trees.
In nature their heights range from one to six metres. However, most of the shrubs can be grown as small trees; indeed, the appearance and habit of some is in that grey zone between shrub and small tree.
Consider that Caragana arborescens, the ‘flagship species,’ is informally called ’Siberian Pea Shrub’ or ‘Siberian Pea Tree’ depending on whom you ask! It is also called ‘Russian Acacia.’
Genus Caragana is a member of Family Fabaceae or the Pea Family.
Not surprisingly, most species’ leguminous fruits are edible. Indeed, in British gardens those few Caragana species that are of interest are a ‘two for the price of one’ deal: they function as ornamental plants as well as edible ones.
But that’s far from all, for the genus as a whole has quite an astonishing breadth of utilitarian functions.
The ‘Swiss Knife’ Shrub
Essentially a Sino-Russian genus, Caragana shrubs are deployed for environmental purposes including erosion control and dune-fixation, and as windbreaks.
The bark and stems provide raw material for making cord and fibre. The foliage is used to produce forage and silage for livestock, the seeds are used to feed chickens, and the flowers supply nectar for honeybees. As for the peas, humans enjoy them in their stews.
The stems and branches are valued for fuelwood in the cold countryside. The leaves are the source of a bluish dye. In common with other leguminous species, Caragana plants improve the soil by fixing nitrogen.
Finally, in China, Tibet, and Mongolia Caragina species have been used for centuries to make very many medicines with which to treat a very wide range of illnesses and diseases.
And this usage has scientific foundation because Caragana plants’ parts contain over 100 phytochemicals.
Whew! What a genus! Caragana must be the Swiss Knife of shrubs.
Pretty Flowers, Tasty Peas
This deciduous shrub has alternate, evenly pinnate compound leaves with each leaf having anything from 4 to 20 leaflets depending on the species. Most species’ foliage is of a deep and bright green hue, and turns yellow in autumn.
The irregular flowers that bloom in spring bring snapdragons to mind. They comprise of a standard, two usually ear-shaped wings, and a keel.
They are small, from 1.5 to 2.5 centimetres depending on the species. Flowers are a shade of yellow, from pale yellow to buttery yellow, in the vast majority of species.
Only a few species produce white, pink, or purple flowers.
As the season wears on, the flowers of many of the species form into edible leguminous pods – and then you’re faced with a choice.
You can pick the pods and enjoy the delicious peas inside. Or you can let the pods mature on the plant, and wait, and wait, and . . . pop!
Caragana pods have the endearing habit of bursting with an audible sound to scatter their seeds. Kids, of course, will love it. The kids will also love the peas, and not only those but also the flowers for they too are not only edible but are quite tasty.
If you live in a townhome in Surrey or on the craggy coastline in the north of Scotland, you can bank on the tough-as-nails Siberian Pea Shrub to supply you with an abundance of buttery flowers as well as buttered peas!
Background & Origins
Ten to twenty million years ago during the Miocene Epoch, when the Himalayas and the Alps were ascending from the earth and the apes were descending from the primates, Caragana were evolving in what we know today as the Tibetan plateau and surrounding arid regions that are now in China.
This plant has been known as ‘Khargana’ for centuries to the indigenous peoples of Russia and China, and from this native name we get ‘Caragana.’
Chinese migrants took this plant to the then British Colonies of America in the mid-1700s. Since then it has become established in California and several other states as an introduced species.
It is in use in the United States for both its ornamental value as well for its utility.
In Europe it was introduced in France and then Czechoslovakia well before landing in the United Kingdom where it is beginning to catch on.
C. arborescens or Siberian Pea Shrub or Siberian Pea Tree is the ‘lead’ species, so to speak, of the genus. Though numerous Caragana species are appreciated and grown for different purposes in China, Tibet, and Russia, this is the most well-known one in the United Kingdom (and the United States as well). It typically grows to 3 to 4.5 metres but may reach up to 6 metres. Its buttery yellow flowers blossom in May or June, and their fragrance and nectar pulls bees and butterflies. The flowers are edible and are tossed in salads, the peas are eaten raw or cooked, and the seeds too can be cooked in dishes. You can very much decide whether C. arborescens becomes a small tree or a shrub by pruning it per your choice. This species also makes excellent bonsai plants.
C. arborescens ‘Walker’ or Walker’s Weeping Pea Shrub is a small tree which has four equidistant stems arching out from the top of the central stem and ‘weeping’ downward. It is a cultivar that needs a little help from its human friends to start ‘weeping’ and attain its form, which is not a natural one. Stems are grafted on the top of the developing trunk. Once grafted, the stems grow outward and downward naturally without reaching the ground or coming close to it. The bright light green leaves are small and fine, even somewhat feathery. It attains a height of only 1.5 to 1.8 metres with a spread of about a metre. It was developed in Manitoba, Canada and is becoming a sought-after variety in both the United Kingdom and the United States.
C. arborescens ‘Pendula’ is similar to C. arborescens ‘Walker’. The two names may be mistaken as synonyms for the same variety but this is not the case. ‘Pendula’ too is a small tree with a weeping form but there are a few points of difference. Its pendulous branches come very close to the ground, and may need to be trimmed. The foliage is quite dense all round the tree but has an airy and fluffed-up look. The bark is noticeably smooth and sheeny. Finally this variety grows from 1.5 metres to an ultimate height of nearly 3 metres with a spread of 1 to 2 metres that is made pronounced by the fluffed-up foliage. It is also experiencing a rise in demand on both sides of the Pond.
C. halodendron or Salt Tree has its own set of aesthetic features. It has a classic ’shrubby’ look with a spreading, bushy habit. It attains a height and spread of up to 2 metres. The leaves are a light silvery green. What makes it different is the colour of its pretty flowers – blush pink to rosy pink. It is native to a belt of land in Central Asia.
C. korshinskii has quite a variable height ranging from 1 to 4 metres. It has the usual yellow flowers but with a short claw. The central stem and branches have a pleasing golden-yellow colour and have a furry nap. This is one of the Caragana species that is a very valuable utility tree for it is planted in poor ground to stabilise the soil and control erosion, and its foliage is used for animal fodder. It is native to Mongolia, Manchuria, and North-Central China.
C. sinica attains heights of 1.5 to 2 metres. It bears insignificant yellow flowers of only a centimetre. It has dark brown bark. This is one of the species that contains medicinal compounds and is much prized in East Asian medicine. Among the valuable compounds found in the roots are acetylcholinesterase inhibitors and protein kinase C inhibitors. It is native to central and eastern China.
C. pygmaea is, as one might expect, a dwarf. It attains a height of only about 50 centimetres. Among its set of special features are golden yellow branches and brilliant green leaves. The yellow flower is 1 to 1.5 centimetres with short upper claws. It is an excellent no-maintenance deciduous shrub for rockeries with poor soil.
Habitat & Growing Conditions
Caragana species grow in an abundance of habitats in China, Russia and Central Asia from desert to forest, taking in grasslands, shrublands, steppes, and hills and mountains.
C. arborescens and most of the species make their homes in infertile and poor soils, including alkaline soils. They withstand a fair amount of drought and aridity. They are immune to exposure and sea spray. Many species grow in frigid conditions well below zero.
As one may expect, a plant with ‘Siberian’ in its name is fully hardy with a hardiness rating of Zone H7, as are most of the other species.
C. arborescens and its cultivars crop reliably and heavily in the eastern part of the United Kingdom but do not do quite as well in the western half because of the difference in rainfall patterns.
Where to Plant Caragana
Caragana tolerates, hmmm – everything! Though its toughness certainly doesn’t mean that you should abuse the plant, it does give the gardener numerous options.
You can use Caraganas to make a decorative windbreak that will offer summer colour and also autumn veggies. A row of suitably pruned Siberian Pea Shrubs could be used to make a pretty and utilitarian low screen (though in winters you will lose the screening effect).
These plants can be treated as flowering bushes and grown in a cottage garden and also in a backyard kitchen garden.
The weeping varieties are, of course, highly ornamental small trees. They are eminently suitable for a courtyard garden.
They will have aesthetic value if planted in a row along a walkway, and also when used as a focal point at the door or by the dwelling’s wall between windows.
Finally, if you have poor soil, a windswept location, a coastal site, or even all three, Caragana is one of the plants that will work very well for you.
Feeding, Care & Growing Tips
Caragana species are very tough plants and do not require much care; the weeping cultivars, on the other hand, do need some attention.
Caragnas should be sited in full sun or at least partial sun.
Though they will thrive even in poor soils, a gravel- and sand-based loam tending from Neutral to Moderately Acidic with organic compost or humus mixed in will allow the plant to flourish. Above all the soil should be well-drained.
Caragana species can be grown from seed, rooted from softwood cuttings, or bought as potted plants.
The drawback to sowing seeds or rooting cuttings is that you will see flowers and pick peas after at least three years, most likely five.
Sow seeds directly outdoors in spring. Scarify and soak half your seeds prior to sowing. Sow them about 1 centimetre deep directly outdoors.
Water in moderation and continue to water the bed. You should see seedlings sprouting in 15 to 20 days. Softwood cuttings too should be rooted in spring.
If you have a potted plant, transplant it in spring, otherwise in summer.
The planting hole should be about as deep as the root system and about twice the width. Put the plant in the hole such that the roots are properly spread out and backfill the hole, making sure the soil level (of the main stem) is the same as it was in the pot and not any higher.
Give it a good watering. Water moderately every two or three days for a few weeks after which you may water it weekly.
Caragana varieties do not need fertilising. However, you may certainly fertilise annually in early spring or mid spring. Use a 0-10-10 liquid fertiliser.
How you prune Caragana arborescens is entirely dependent on whether you want a Siberian Pea Shrub or a Siberian Pea Tree.
For the former, you will pinch out the tip, control the height, and encourage early branching and bushiness; for the latter, you will promote the leader, prune sideshoots, and discourage early branching.
Pruning Caragana also strongly depends on how you want to use these multi-purpose plants.
For instance, if you want to create a flowering hedge that functions as a windbreak using Caragana, then you will have to prune the plants accordingly, by cutting back the stems to begin with.
Do not prune the weeping cultivars other than to trim branches that may touch the ground and to remove shoots that may emerge from the side of the trunk.
If you pick the pods when they are young, very soon after they form, the tender peas inside can even be enjoyed raw. However, it is not a problem if you pick them a little late, for more mature peas are perfectly fine in cooked dishes.
Common Diseases and Problems
Caragana is not known to suffer from any pests or diseases.
Birds may take a liking to the pods so you may have to guard your peas from being consumed before you get to them.
Where to Buy Caragana
Caragana is not exactly a freely available plant and you may or may not be able to find it at a nearby brick-and-mortar garden centre.
Also, it is unlikely that you will find a wide range of species and cultivars.
Your best bet would be to check out online nurseries that specialise in shrubs and trees, and in veg and herb.
Kersie learnt the basics of gardening as a toddler, courtesy of his grandfather. In his youth he was an active gardener with a preference for flowering plants. He is a professional and vocational writer and his freelance projects have spanned various kinds of writing.