Plant of the Week #9: Caragana arborescens

This is one of those cases where pretty much all of us have taken at least a passing glimpse at a Siberian pea-tree, also known as Siberian pea-shrub or simply Caragana (Caragana arborescens) many times but outside of the gardening world no one really pays attention to it; it’s simply another shade of green that blends in with the peripheral landscape of more familiar things. It tends to stand out most in spring, when it’s bright tender foliage emerges in sync with vibrant yellow pea-shaped blossoms. This handsome woody legume is your 9th plant of the week.

Out of those of us who are familiar with A. arborescens, few are acquainted with it’s potential as a one-hit-wonder for those considering investing their time and energy into growing useful and practical plants which also happen to be showy. I was, and still am, shocked at how belittled this species is in modern cultivation despite how unknowingly rich it’s history is here in North America and elsewhere.  My aim here is to dispel, for the most part, any reasons as to why we overlook such a highly adaptable and prolific species and how they can contribute to future food security among other blessings.

The Siberian pea-tree is an extremely hardy (tolerating winter temperatures down to -40°C) multi-stemmed shrub in the legume family Fabaceae. It can grow to be a wide, sprawling multi-stemmed tree several meters or around 10-11 feet tall (growing up to 4 feet per year) if left to it’s own devices but can withstand heavy pruning and is occasionally shaped into hedges or as a dwarfed pendulous specimen with a single trunk: one of it’s more popular horticultural forms. Branches are often outward growing and arching, adding as much width as height to the Siberian pea-tree’s overall growth habit.

The species was originally brought to North America as a food crop, the seeds having been brought here deliberately centuries ago by early Russian and North-west Asian immigrants. As the families and communities moved west over the years, they sowed the seeds as they traveled so that populations of these plants would naturalized and provide sustenance in case of an emergency such as the failure of a particular crop. For now, it finds itself planted widely by municipalities and home-owners alike, valued not for it’s life-preserving potential but as an attractive and hardy ornamental.

The leaves, which emerge in mid-spring and are retained quite late into the year, are dark green, pinnately compound with 6-14 smooth, abruptly pointed elliptical leaflets that grow alternately and often lack a terminal leaflet. Dwarf shoots which grow out of the main branches bear tufts of bright yellow flowers soon after the leaves emerge and develop into smooth, light green 3-5cm long pods with tapered ends which contain 2-4 seeds each. The flowers are edible, with a sweet, juicy and crunchy texture and can be added to sandwiches, salads or used as a garnish or ‘garden nibble’.

The young seeds, similar to peas, are also edible and taste much like the latter and can be used the same way. Before the pods get too large and tough, they can be eaten whole and prepared like snow or snap peas and sautéed. The seed pods dry and mature in late summer or early autumn and conceal light to dark brown or red/brown speckled or striped ‘beans’ which are also edible and can be used in the same way as dry beans. Naturally, they scattered when the pods dry sufficiently and split open, the seeds germinating freely and forming monocultural thickets around the original plant.

Although appearing quite sparse from afar, these plants bear seed prolifically and reliably every year. They are self fertile.
Although appearing quite sparse from afar, these plants bear seed prolifically and reliably every year. They are also self fertile.

One of the many features that I look for reliable perennial crop is it’s ability to produce more than a single harvestable ‘product’. Although the season for each individual ‘product’ (flowers, seed pods, peas or dried seeds etc.) is relatively short, the time span in which some sort of edible treat can be collected from this plant essentially stretches nearly the entire growing season from late spring to autumn. This means that even though you might not be available to take advantage of all that the Siberian pea-tree has to offer, in a time of need when there are few other garden plants that happen to be producing, this species makes an excellent fall-back crop that is a great resource to have around.

It may not be your absolute favorite edible plant in your collection or the most delicious, but it is sturdy, reliable and will be there for you if you need it. In the mean time, even if you are not graciously accepting the various edibles that it produces all year, it provides other ecological services all the time including soil stabilization, acting as a windbreak, providing shade for more delicate or woodland plant species and like many other legumes, enriches the soil through it’s ability to fix atmospheric nitrogen. Siberian pea-tree is often planted along highway embankments, on slopes, bordering roadways or as property markers and windbreaks in fence rows and across farmland.

The plants are extremely tolerant of poor soils, exposed locations (they can deal with almost constant wind and salt-spray from maritime exposure), compacted or heavy soils and prolonged periods of intense cold in the winter months. They do, however, require at least part or mostly direct sunlight during the day and will not tolerate damp, poorly drained soils or very light sandy soils. Over time, these shrubs will naturally become shaded out by taller shrubs and trees, allowing the potential for them to be integrated into food and medicine producing ecosystems with natural succession in mind.

Many grazing animals such as goats, sheep and cattle and horses also enjoy grazing on the foliage, and the plants are tough enough to handle moderated browsing. As the name implies, this species is as native of Siberia and north-eastern Asia which may make this species inappropriate for those ecological purists who would only like to deliberately cultivate native species. I definitely encourage this and practice it as much as I can, although it seems foolish to discriminate against such as hard working and rewarding introduced plant.

The flora and fauna of the world, in my mind, has become so homogenized to the extent that attempting to reverse our own effects on the environment and designating them as ‘negative influences’ is not only impossible but also impractical. I think our time is better spent learning to adapt to a changing world and dealing with the changes that have already occurred, rather than dedicating so much time bailing water out of a leaky boat when our global community continues to spread seeds and creatures around the world through the same means (whether deliberate or accidental) that it has been for centuries.

Specimens for seed or cuttings are not difficult to come by in an urban and paved environment. This individual is growing near the corner of Queenston and Centennial in Hamilton, perhaps one of the busiest intersections in the city.
Specimens for seed or cuttings are not difficult to come by in an urban and paved environment. This individual is growing near the corner of Queenston and Centennial in Hamilton, perhaps one of the busiest intersections in the city.

Another attribute that I include as part of my ideal features of any cultivated plants is ease of propagation. The seeds, if left on the shrub during the winter, can be collected in the spring, soaked in water for 24 hours and if planted in nutrient rich, well-drained soil should germinate in 2-3 weeks. In summer, 7-10cm long cuttings of semi-ripe wood (current years growth) can be taken and planted in soil in a container. Over the course of the rest of the year, if they are kept moist, the cuttings should root and can be planted out in their permanent locations the following year.

I am also aware of root division or suckers being separated from the parent shrub and transplanted out with success, although I have heard mixed reviews regarding these last methods and have not tried them out myself. Seed is probably the best method to go with if you do not have prior experience with cuttings, but the plants are hardy and their will to live is likely just as strong as your desire to see them perform well. If you are curious about utilizing this plant but are not necessarily ready to invest in one without a test drive, it is likely that a park or nearby home has a Siberian pea-shrub growing with which you can (with permission) sample and propagate if you decide to.