Caragana: Where And How To Grow The Incredibly Hardy ‘Siberian Peatree’
Reviewed By DAN ORI
Dan has over 27 years’ under his belt caring for plants and gardens. Working as a Horticultural Instructor and Consultant, he draws on a diverse range of experience that includes working as a Head Gardener, Tree Surgeon, Garden Centre Trouble Shooter, and writer of academic papers. Dan has a Level 3 Diploma in Horticulture and is currently a candidate for the RHS’s most prestigious award – The Master of Horticulture.
IN THIS GUIDE
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 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!
Overview
| Botanical Name | Caragana arborescens |
| Common Name(s) | Siberian Pea Tree, Siberian Pea Shrub |
| Plant Type | Tree / Shrub |
| Native Area | Siberia / Manchuria |
| Hardiness Rating | H7 |
| Foliage | Deciduous |
| Flowers | Pale yellow flowers, followed by pods |
| When To Plant | January, February, March, November, December |
| Flowering Months | June, July |
| Harvesting Months | September, October |
Sunlight
Preferred
Full Sun
Exposure
Sheltered or Exposed
Size
Height
4 – 8M
Spread
2.5 – 4M
Bloom Time
May – July
Soil
Preferred
Loam, sand
Moisture
Well-drained or moist but well-drained
pH
Any
This is a genus of about 90 species, the vast majority of which are shrubs and only a few are small trees.1Caragana. (n.d.). Kew Royal Botanic Gardens. Retrieved March 14, 2023, from https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21935-1
In nature their heights range from 1-6m – 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.2Caragana frutex. (n.d.). North Carolina Extension Gardener Plant Toolbox. Retrieved March 14, 2023, from https://plants.ces.ncsu.edu/plants/caragana-frutex/
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.
Essentially a Sino-Russian genus, Caragana shrubs are deployed for environmental purposes including erosion control and dune-fixation, and as windbreaks.
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.
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 and 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 are said to crop reliably and heavily in the eastern part of the UK but not quite as well in the western half, because of the difference in rainfall patterns.
Where To Grow Caragana
Caragana tolerates, hmmm – everything! Its toughness 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.
How To Grow Caragana
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 1cm deep directly outdoors.
- Water in moderation and continue to water the bed.
- You should see seedlings sprouting in 15-20 days.
Softwood cuttings too should be rooted in spring.
Planting
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.
“Good weekly water during spring, summer, and dry autumn will help the health and establishment of your Caragana and will also give you the best chance of a good harvest,” shares Horticulturist Dan Ori.
Ongoing Care
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.
Soil
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.
Feeding
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.
Pruning Caragana
How you prune C. 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 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.
Common Varieties
C. arborescens
AKA: Siberian Pea Shrub or Siberian Pea Tree
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 UK (and the USA as well).
It typically grows to 3-4.5m but may reach up to 6m.
Its buttery yellow flowers blossom in May or June, and their fragrance and nectar pulls bees and butterflies.
You can very much decide whether C. arborescens becomes a small tree or a shrub by pruning it per your choice – while this species also makes excellent bonsai plants.
C. arborescens ‘Walker’
AKA: Walker’s Weeping Pea Shrub
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 1.5-1.8m with a spread of about 1m.
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’
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 1.5m to an ultimate height of nearly 3m with a spread of 1-2m that is made pronounced by the fluffed-up foliage.
It is also experiencing a rise in demand on both sides of the Pond.
C. sinica
Attains heights of 1.5-2m.
It bears insignificant yellow flowers of only 1cm.
It has dark brown bark and is native to central and eastern China.
C. pygmaea
Is, as one might expect, a dwarf variety.
It attains a height of only about 50cm.
Among its set of special features are golden yellow branches and brilliant green leaves.
The yellow flower is 1-1.5cm with short upper claws.
It is an excellent no-maintenance deciduous shrub for rockeries with poor soil.
