Welcome to the 4th installment of Plant of the Week! The list of subjects for future editions is continuing to grow, faster than there are Mondays in a month and I sincerely hope that this trend continues. Just last Monday in fact (when I posted my last article on the stone pine, Pinus cembra) I happened to be walking through a part of the Wildwood Park neighborhood here in Winnipeg and stumbled upon a European barberry (Berberis vulgris) shrub adorned in hundreds if not thousands of bright red berries. It is this species and a few relatives from around the world that I’ll be showcasing for you today.
Although back home in Ontario I was quite accustomed to encountering this rugged, spiny, multi-stemmed shrub naturalized along forest edges, fence rows and trail sides as well as intentionally planted with care in parks and gardens I did not expect to see it here along the eastern fringes of Canada’s great prairies. I was pleasantly surprised, not just because of the new found understanding that B. vulgaris has the capacity to survive here but that it actually thrives here. Never before have I seen an individual exhibit this level of fecundity, and thus I developed a refreshed respect for this plant and felt that I should honor it and it’s kin.
As soon as I returned home from my outing I had already made up my mind that B. vulgaris was going to be the focus of my next article. It just had to be! The timing of my encounter was too appropriate. I had to learn more about these tough, beautiful and widely diverse plants, some of which have remarkable stories to tell. Since I can’t cover everything that I would like to say in a single article I’ll have to stick to the species which I have found to be the most relevant for those of us living in north temperate climates, as is supposed to be the goal of this weekly series but it easy to get off track.
The European barberry, as the name suggests, is indigenous to quite a large area of central and southern Europe including north Africa and western Asia and tolerates quite a range of sun and soil conditions, including rocky or gravelly environments, sandy sites and fairly heavy clay. It flowers and yields fruit profusely in full sun exposure but it also succeeds in on the peripheries of woodland, in hedgerows or sunny clearings along trails. B. vulgaris was introduced to North America as an ornamental shrub (which it most certainly is) but quickly made itself comfortable and eagerly escaped into wild spaces surrounding cities and towns but appears to not wish to stray too far.
The growth habit of B. vulgaris is characteristic and can often be discerned from afar as (at least in Canada) it has few imitators. Comprised of multitudes of numerous intertwining shoots which emerge from the base of the plant, the European barberry often grows to a height of 7 or 8 feet and will aggressively sprout when cut back to the ground or pruned. The flexible branches initially grow upwards but eventually begin arching back towards the ground, producing from them variable though roughly elliptical foliage with finely serrated margins and blunt tips which taper to the base on short petioles. The leaves are borne in clusters or whorls of 3-5 with a 3 or 5 pronged spines at their base.
Along the branches emerge stubby dwarf shoots which between clusters of foliage are borne nodding panicles of bell shaped blossoms. These fragrant yellow flowers, when pollinated yield oblong red berries containing 2 elongated seeds. The juicy berries mature in late summer or early autumn and are edible and nutritious, containing large quantities of vitamin C as well as minerals and other nutrients. They are however quite sour and so are often cooked with sweeter fruit or mixed with sugar or honey when making preserves.
The berries do become slightly sweeter after they’re exposed to a few light frosts although they are often still noticeably tart and aren’t usually eaten fresh even though they are remarkably refreshing. Despite this, barberries have been cultivated in parts of Central Asia including Iran and are common in many Persian rice recipes where they are often sautéed in butter and sugar. There are also a wide variety of different recipes for barberry wine as well, where they are fermented alone with sugar added or mixed with sweeter fruit. The resulting beverage is distinctly tart and dry, with an intense color and mouth-watering aroma.
The young foliage is also edible and is too quite sour, reminiscent of sorrel or dock (Rumex spp.) leaves. Although not as commonly consumed as the fruit, the foliage can be chopped finely and added to salads, used to garnish soup or incorporated into mashed or boiled potatoes just before serving to add some brightness. The berries, if not discovered by some overwintering birds, often remain on the plants until the next spring where on occasion last year’s fruit and the current seasons’s blossoms can be viewed together.
The genus Berberis is considerably diverse with representatives that are found throughout the temperate and subtropical world. South America, Africa and parts of Asia host the highest diversity of individual species, with many horticulturally significant species coming from these parts of the world. For example, the South American B. darwinii (named by Charles Darwin himself) is one of the most visually striking of the group with dense, glossy evergreen foliage fringed with course spines and brilliant yellow-orange spring blossoms from which large, dark purple berries are produced.
The box-leaved barberry (B. microphylla)* is another spinier species from South America which, although not quite as showy as B. darwinii produces even larger purple-black berries with a glaucous blue coating that are sweet and delicious eaten straight off the plant. While the former species cannot be successfully cultivated in Canada except for perhaps the south western coast of British Columbia, B. microphylla can be cultivated in at least zone 5b if not up to parts of zone 4 for it’s lovely solitary blossoms, compact habit and delicious fruit.
One of the most common ornamental barberries you see in Canada today is the Japanese barberry (B. thunbergii), which is shorter both in stature and form than B. vulgaris and also has smaller and rounder leaves without serrated edges, berries that aren’t borne in drooping panicles and solitary spines. B. thunbergii is often encountered as a low hedge or shaped into a small shrub in gardens as it tolerates pruning quite well and adapts to a wide range of soil types and light levels. Although the fruit can also be eaten it tends to be of lesser quality than it’s European cousin, as it is often mealier in texture and without taste.
The clustered barberry (B. aggregata) is an Asiatic species native to China that can also be grown in zone 5 in Canada. As the name implies, the nearly sessile salmon pink berries are produced in congested clusters along the stems which makes harvesting considerably easier than on species where the berries are produced individually. B. jamesiana is yet another highly productive Chinese barberry that can grow to a height of 12 feet or more and yields voluminous dangling clusters of berries which undergo shades of white and pink as they ripen. Unfortunately this species is once again unavailable to gardeners other than those in south western B.C.
Back home in the western world, the American barberry (B. canadensis) is a native of the eastern United States (but ironically not southern Canada) and is similar in many ways to B. vulgaris. Interestingly and unfortunately, the American barberry was almost completely eradicated in the wild due to a fungus (Puccinia graminis) which spends part of it’s reproductive life cycle on Beberbis shrubs before releasing airborne spores which germinate on the leaves of wheat and other grains. Often appearing in fields in late summer, this fungus (known as wheat or black stem rust) can reach epidemic proportions virtually overnight and causes extensive damage to the plants, often decimating crop yields by up to 60%.
In an effort to prevent the spread and continued seasonal onslaught of this new devastating agricultural disease, a total of 18 states in cooperation and support from the Federal government initiated the Barberry Eradication Program in 1918 after the record low harvests of 1916. The goal of this program was to effectively extirpate both the native B. canadensis as well as the then introduced B. vulgaris (since the fungus infected both species indiscriminately) from their collective distributions which encompassed a large swath of eastern North America where much of the country’s cereal grains were grown at the time.
All demographics from church clubs to school children were recruited and passionately participated in one of the most extensive botanical mass murders ever orchestrated. Over the ensuing decades and by the time the program was phased out between 1975 and 1980, over 500 million barberry shrubs were hunted down and dug up from suburban gardens, farm yards, fallow fields or forests, their mangled corpses piled up in courtyards and neighborhoods and destroyed.
I am somewhat reluctant to acknowledge the justification of this biological genocide due to my obvious bias considering the great indignity that these plants had to suffer due to no real fault of their own. However, the ecological repercussions caused by the virtual elimination of a single species from the environment (together with the disturbance that decades of foot traffic through otherwise largely undisturbed areas would have caused) is certainly not something to disregard. If there are any instances at all of poaching or ‘ecological cleansing’ to be founded within the plant world then this is certainly it.
Due to their remoteness and inaccessibility, the mountains of Virginia appear to be one of the last strongholds for B. canadensis (which is as of this writing currently listed as ‘vulnerable’ under the Nature Conservancy’s NatureServe index) although isolated populations can still be found growing in other localities within it’s former range on steep hills and mountainsides where they luckily evaded harassment. If you would like to learn more about the Barberry Eradication program and it’s effects on American history, ecology and agriculture, then I highly recommend you check out this article written by the American Phytopathological Society.
* Berberis microphylla is also sometimes known by it’s synonym Berberis buxifolia in the horticultural trade from which the common named box-leaves barberry is derived. ‘Box’ is the common name for the Buxus genus, a group of mostly evergreen Old-World shrubs (hence buxifolia or box-leaved). These plants are also extensively cultivated and utilized as low hedges or are grown larger and shaped into topiary.