The blackberry is an edible fruit produced by any of several species in the Rubus genus of the Rosaceae family. The fruit is not a true berry; botanically it is termed an aggregate fruit, composed of small drupelets. The plants typically have biennial canes and perennial roots. Blackberries and raspberries are also called caneberries or brambles. It is a widespread, and well known group of over 375 species, many of which are closely related apomictic microspecies native throughout the temperate Northern Hemisphere and South America.
Growth and anatomical description
In its first year, a new stem, the primocane, grows vigorously to its full length of 3–6 m (in some cases, up to 9 m), arching or trailing along the ground and bearing large palmately compound leaves with five or seven leaflets; it does not produce any flowers. In its second year, the cane becomes a floricane and the stem does not grow longer, but the lateral buds break to produce flowering laterals (which have smaller leaves with three or five leaflets). First and second year shoots usually have numerous short curved very sharp prickles that are often erroneously called thorns. Prickle-free cultivars have been developed. Recently the University of Arkansas has developed primocane fruiting blackberries that grow and flower on first year growth much as the primocane-fruiting (also called fall bearing or everbearing) red raspberries do.
Unmanaged mature plants form a tangle of dense arching stems, the branches rooting from the node tip on many species when they reach the ground. Vigorous and growing rapidly in woods, scrub, hillsides and hedgerows, blackberry shrubs tolerate poor soils, readily colonizing wasteland, ditches and vacant lots.
The drupelets only develop around ovules that are fertilized by the male gamete from a pollen grain. The most likely cause of undeveloped ovules is inadequate pollinator visits. Even a small change in conditions, such as a rainy day or a day too hot for bees to work after early morning, can reduce the number of bee visits to the flower, thus reducing the quality of the fruit. Incomplete drupelet development can also be a symptom of exhausted reserves in the plant's roots, or infection with a virus such as Raspberry bushy dwarf virus.
Blackberry leaves are food for certain caterpillars; some grazing mammals, especially deer, are also very fond of the leaves. Caterpillars of the concealer moth Alabonia geoffrella have been found feeding inside dead blackberry shoots. When mature, the fruits are eaten and their seeds dispersed by several mammals, such as the red fox and the Eurasian badger, as well as by small birds.
Cultivation and uses
Primary cultivation takes place in the state of Oregon located in the United States of America. Oregon is the leading blackberry producer in the world, producing 42.6 million pounds on 6,180 acres (25.0 km2), in 1995 and 56.1 million pounds on 7,000 acres (28 km2) in 2009. While Oregon may lead the world in volume of fruit produced, Serbia has tremendous acreage.
The blackberry is known to contain polyphenol antioxidants, naturally occurring chemicals that can upregulate certain beneficial metabolic processes in mammals. The astringent blackberry root is sometimes used in herbal medicine as a treatment for diarrhea and dysentery. The related but smaller dewberry can be distinguished by the white, waxy coating on the fruits, which also usually have fewer drupelets. (Rubus caesius) is in its own section (Caesii) within the subgenus Rubus.
In some parts of the world, such as in Australia, Chile, New Zealand and the Pacific Northwest region of North America, some blackberry species, particularly Rubus armeniacus (syn. R. procerus, 'Himalaya') and Rubus laciniatus ('Evergreen') are naturalised and considered an invasive species and a serious weed.
As there is forensic evidence from the Iron Age Haraldskær Woman that she consumed blackberries some 2500 years ago, it is reasonable to conclude that blackberries have been eaten by humans over thousands of years.
Diseases and pests
|This section requires expansion.|
The spotted-wing drosophila, Drosophila suzukii is a serious pest of blackberries. Unlike its vinegar fly relatives which are primarily attracted to rotting or fermented fruit, D. suzukii attacks fresh, ripe fruit by laying eggs under the soft skin. The larvae hatch and grow in the fruit, destroying the fruit's commercial value.
Numerous cultivars have been selected for commercial and amateur cultivation in Europe and the United States. Since the many species form hybrids easily, there are numerous cultivars with more than one species in their ancestry.
'Marion' (marketed as "marionberry") is an important cultivar that was selected from seedlings from a cross between 'Chehalem' and 'Olallie' (commonly called "olallieberry") berries. 'Olallie' in turn is a cross between loganberry and youngberry. 'Marion', 'Chehalem' and 'Olallie' are just three of many trailing blackberry cultivars developed by the United States Department of Agriculture Agricultural Research Service (USDA-ARS) blackberry breeding program at Oregon State University in Corvallis, Oregon.
The most recent cultivars released from this program are the prickle-free cultivars 'Black Diamond', 'Black Pearl' and 'Nightfall' as well as the very early ripening 'Obsidian' and 'Metolius'. 'Black Diamond' is now the leading cultivar being planted in the Pacific Northwest. Some of the other cultivars from this program are 'Waldo', 'Siskiyou', 'Black Butte', 'Kotata', 'Pacific' and 'Cascade'.
Trailing blackberries are vigorous, crown forming, require a trellis for support, and are less cold hardy than the erect or semi-erect blackberries. In addition to the U.S. Pacific Northwest, these types do well in similar climates such as the United Kingdom, New Zealand, Chile, and the Mediterranean countries.
Semi-erect, prickle-free blackberries were first developed at the John Innes Centre in Norwich, UK, and subsequently by the USDA-ARS in Beltsville, Maryland. These are crown forming, very vigorous, and need a trellis for support. Cultivars include 'Black Satin' 'Chester Thornless', 'Dirksen Thornless', 'Hull Thornless', 'Loch Ness', 'Loch Tay', 'Merton Thornless', 'Smoothstem' and 'Triple Crown'. Recently, the cultivar 'Cacanska Bestrna' (also called 'Cacak Thornless') has been developed in Serbia and has been planted on many thousands of hectares there.
The University of Arkansas has developed cultivars of erect blackberries. These types are less vigorous than the semi-erect types and produce new canes from root initials (therefore they spread underground like raspberries). There are prickly and prickle-free cultivars from this program, including 'Navaho', 'Ouachita', 'Cherokee', 'Apache', 'Arapaho' and 'Kiowa'. They are also responsible for developing the primocane fruiting blackberries such as 'Prime-Jan' and 'Prime-Jim'.
In raspberries, these types are called primocane fruiting, fall fruiting, or everbearing. 'Prime-Jim' and 'Prime-Jan' were released in 2004 and are the first cultivars of primocane fruiting blackberry. They grow much like the other erect cultivars described above, however the canes that emerge in the spring, will flower in mid-summer and fruit in late summer or fall. The fall crop has its highest quality when it ripens in cool mild climate such as in California or the Pacific Northwest.
'Illini Hardy' a semi-erect prickly cultivar introduced by the University of Illinois is cane hardy in zone 5, where traditionally blackberry production has been problematic, since canes often failed to survive the winter.
The blackberry tends to be red during its unripe ("green") phase, leading to an old expression that "blackberries are red when they're green".
In various parts of the United States, wild blackberries are sometimes called "Black-caps", a term more commonly used for black raspberries, Rubus occidentalis.
Blackberry production in Mexico has expanded enormously in the past decade. While once based on the cultivar 'Brazos', an old erect blackberry cultivar developed in Texas in 1959, the Mexican industry is now dominated by the Brazilian 'Tupi' released in the 1990s. 'Tupi' has the erect blackberry 'Comanche' and a "wild Uruguayan blackberry" as parents. Since there are no native blackberries in Uruguay, the suspicion is that the widely grown 'Boysenberry' is the male parent. In order to produce these blackberries in regions of Mexico where there is no winter chilling to stimulate flower bud development, chemical defoliation and application of growth regulators are used to bring the plants into bloom.
Nutrients and antioxidant qualities
|Nutritional value per 100 g (3.5 oz)|
|Energy||180 kJ (43 kcal)|
|- Dietary fibre||5.3|
|Vitamin A||214 IU|
|- beta-carotene||128 μg (1%)|
|- lutein and zeaxanthin||118 μg|
|Vitamin C||21 mg (25%)|
|Vitamin E||1.17 mg (8%)|
|Vitamin K||20 μg (19%)|
|Calcium||29 mg (3%)|
|Iron||0.62 mg (5%)|
|Magnesium||20 mg (6%)|
|Manganese||0.6 mg (29%)|
|Potassium||162 mg (3%)|
|Sodium||1 mg (0%)|
|Zinc||0.53 mg (6%)|
|Percentages are relative to|
US recommendations for adults.
Source: USDA Nutrient Database
Blackberries rank highly among fruits for antioxidant strength, particularly due to their dense contents of polyphenolic compounds, such as ellagic acid, tannins, ellagitannins, quercetin, gallic acid, anthocyanins and cyanidins.
Blackberries have an ORAC value (oxygen radical absorbance capacity) of 5347 per 100 grams, including them among the top-ranked ORAC fruits. Another report using a different assay for assessing antioxidant strength placed blackberry at the top of more than 1000 antioxidant foods consumed in the United States.
Nutrient content of seeds
Blackberries contain numerous large seeds that are not always preferred by consumers. The seeds contain some oil which is rich in omega-3 (alpha-linolenic acid) and -6 fats (linoleic acid), as well as some protein, dietary fiber, carotenoids, ellagitannins and ellagic acid.
Folklore in the UK holds that blackberries should not be picked after Old Michaelmas Day (11 October) as the devil has claimed them, having left a mark on the leaves by urinating or spitting on them. There is some value behind this legend as wetter and cooler weather often allows the fruit to become infected by various molds such as Botryotinia which give the fruit an unpleasant look and may be toxic.
- Black Raspberry, a North American fruit sometimes confused with blackberries.
- Kotata Berry, USDA-ARS release in cooperation with Oregon State University.
- List of Lepidoptera that feed on Rubus
- Redberry mite, a common pest of North American blackberry crops.
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- Historic-UK.com Michaelmas Facts
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