Black raspberry (Rubus occidentalis).
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The raspberry (plural, raspberries) is the edible fruit of a multitude of plant species in the subgenus Idaeobatus of the genus Rubus; the name also applies to these plants themselves. The name originally referred to the European species Rubus idaeus, with red fruit, and is still used for that species as its standard English name in its native area. Several other species, mostly closely related in the same subgenus Idaeobatus, are now also called raspberries. Raspberry species include:
Raspberries are an important commercial fruit crop, widely grown in all temperate regions of the world. Many of the most important modern commercial red raspberry cultivars derive from hybrids between R. idaeus and R. strigosus. Some botanists consider the Eurasian and American red raspberries to all belong to a single, circumboreal species, Rubus idaeus, with the European plants then classified as either R. idaeus subsp. idaeus or R. idaeus var. idaeus, and the native North American red raspberries classified as either R. idaeus subsp. strigosus, or R. idaeus var. strigosus.
The black raspberry, Rubus occidentalis, is also occasionally cultivated in the United States, providing both fresh and frozen fruit as well as jams, preserves, and other products, all with that species' distinctive, richer flavor.
Purple-fruited raspberries have been produced by horticultural hybridization of red and black raspberries, and have also been found in the wild in a few places (for example, in Vermont) where the American red and the black raspberries both grow naturally. The name Rubus × neglectus has been applied to these native American plants. Commercial production of purple raspberries is rare.
The commercially grown red and black raspberry species each have albino-like pale-fruited variants, most generally due to expression of recessive genes affecting production of anthocyanin pigments. Variously called golden raspberries, yellow raspberries, or (rarely) orange raspberries, these fruits retain the distinctive flavor of their respective species, despite their similarity of appearance. In the eastern United States, at least, most commercially sold pale-fruited raspberries are derivatives of red raspberries. Yellow-fruited variants of the black raspberry occur occasionally as wild plants (for example, in Ohio), and are sometimes grown in home gardens.
Raspberries are grown for the fresh fruit market and for commercial processing into individually quick frozen (IQF) fruit, purée, juice, or as dried fruit used in a variety of grocery products. Traditionally, raspberries were a mid-summer crop, but with new technology, cultivars, and transportation, they can now be obtained year-round. Raspberries need ample sun and water for optimal development. While moisture is essential, wet and heavy soils or excess irrigation can bring on Phytophthora root rot which is one of the most serious pest problems facing red raspberry. As a cultivated plant in moist temperate regions, it is easy to grow and has a tendency to spread unless pruned. Escaped raspberries frequently appear as garden weeds, spread by seeds found in bird droppings.
Two types of most commercially grown kinds of raspberry are available, the summer-bearing wild type that produces an abundance of fruit on second-year canes (floricanes) within a relatively short period in mid-summer, and double- or "ever"-bearing plants, which also bear some fruit on first-year canes (primocanes) in the late summer and fall, as well as the summer crop on second-year canes. Raspberries can be cultivated from hardiness zones 3 to 9.
Raspberries are traditionally planted in the winter as dormant canes, although planting of tender,plug plants produced by tissue culture has become much more common. A specialized production system called "long cane production" involves growing canes for 1 year in a northern climate such as Scotland (UK) or Washington State (US) where the chilling requirement for proper budbreak is met early. These canes are then dug, roots and all, to be replanted in warmer climates such as Spain where they quickly flower and produce a very early season crop. Plants should be spaced 1 m apart in fertile, well drained soil; raspberries are usually planted in raised beds/ridges if there is any question about root rot problems.
Raspberries are very vigorous and can be locally invasive. They propagate using basal shoots (also known as suckers); extended underground shoots that develop roots and individual plants. They can sucker new canes some distance from the main plant. For this reason, raspberries spread well, and can take over gardens if left unchecked.
The fruit is harvested when it comes off the torus/receptacle easily and has turned a deep color (red, black, purple, or golden yellow, depending on the species and cultivar). This is when the fruits are most ripe and sweetest. Excess fruit can be made into raspberry jam or frozen.
An individual raspberry weighs about 4 g, on average and is made up of around 100 drupelets, each of which consists of a juicy pulp and a single central seed. Raspberry bushes can yield several pounds of fruit (or several hundred berries) a year. Unlike blackberries and dewberries, a raspberry has a hollow core once it is removed from the receptacle.
Red raspberries (Rubus idaeus and/or Rubus strigosus) have been crossed with the black raspberry (Rubus occidentalis) to produce purple raspberies, and with various species in other subgenera of the genus Rubus, resulting in a number of hybrids, such as boysenberry and loganberry. Hybridization between the familiar cultivated raspberries and a few Asiatic species of Rubus is also being explored.
|Red, early summer fruiting ||Red, primocane, fall, autumn fruiting |
|Nutrients in raw raspberries|
|Nutrient||Value per 123 grams||% Daily Value|
|Fiber, total dietary||8 g||32%|
|Sugars, total||5.4 g|
|Calcium, Ca||30.7 mg||3%|
|Magnesium, Mg||27.1 mg||7%|
|Iron, Fe||0.8 mg||5%|
|Manganese, Mn||0.8 mg||41%|
|Potassium, K||186 mg||5%|
|Sodium, Na||1.2 mg||0%|
|Vitamin C, total ascorbic acid||32.2 mg||54%|
|Vitamin A, IU||40.6 IU||1%|
|Vitamin K, mcg||9.6 mcg||12%|
|Folate, mcg||25.8 mcg||6%|
|Lutein + zeaxanthin||167 mcg||ne|
Raspberries contain significant amounts of polyphenol antioxidants such as anthocyanin pigments linked to potential health protection against several human diseases. The aggregate fruit structure contributes to its nutritional value, as it increases the proportion of dietary fiber, placing it among plant foods with the highest fiber contents known, up to 20% fiber per total weight. Raspberries are a rich source of vitamin C, with 30 mg per serving of 1 cup (about 50% daily value), manganese (about 60% daily value) and dietary fiber (30% daily value). Contents of B vitamins 1-3, folic acid, magnesium, copper and iron are considerable in raspberries.
Raspberries rank near the top of all fruits for antioxidant strength, particularly due to their dense contents of ellagic acid (from ellagotannins), quercetin, gallic acid, anthocyanins, cyanidins, pelargonidins, catechins, kaempferol and salicylic acid. All these are polyphenolic antioxidants with promising health benefits under current research. Yellow raspberries and others with pale-colored fruits are lower in anthocyanins.
Due to their rich contents of antioxidant vitamin C and the polyphenols mentioned above, raspberries have an ORAC value (oxygen radical absorbance capacity) of about 4900 per 100 grams, including them among the top-ranked ORAC fruits. Cranberries and wild blueberries have around 9000 ORAC units and apples average 2800.
The following anti-disease properties have been isolated in experimental models. Although there are no clinical studies to date proving these effects in humans, preliminary medical research shows likely benefit of regularly consuming raspberries against: