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 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. Recent breeding has resulted in cultivars that are thornless and more strongly upright, not needing staking.
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 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 botanical name Rubus × neglectus applies to these naturally occurring plants, as well as horticulturally produced plants having the same parentage. Commercial production of purple-fruited raspberries is rare.
Both the red and the black raspberry species have albino-like pale-yellow natural or horticultural variants, resulting from presence of recessive genes that impede production of anthocyanin pigments. Fruits from such plants are called golden raspberries or yellow raspberries; despite their similar appearance, they retain the distinctive flavour of their respective species (red or black). Most pale-fruited raspberries commercially sold in the eastern United States are derivatives of red raspberries. Yellow-fruited variants of the black raspberry are sometimes grown in home gardens.
Cultivation
Various kinds of 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 a year in a northern climate such as Scotland or Oregon or Washington, where the chilling requirement for proper bud break is attained, or attained earlier than the ultimate place of planting. 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 are typically planted 2-6 per m in fertile, well drained soil; raspberries are usually planted in raised beds/ridges, if there is any question about root rot problems.
The flowers can be a major nectar source for honeybees and other pollinators.
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.
Raspberries are often propagated using cuttings, and will root readily in moist soil conditions. Using cuttings preserves the genotype of the parent, and is the preferred method of propagation when making large plantings.
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 ripest and sweetest. Excess fruit can be made into raspberry jam or frozen.
Advantage of Raspberry
Diet-Friendly
A cup of fresh raspberries contains about 1.5 g of protein, 8 g of dietary fiber, and 14.7 g of carbohydrates. Cholesterol-free, low in fat and sodium, and weighing in at a modest 64 calories per cup, raspberries are a good choice for dieters. The generous amount of fiber they provide -- with one cup supplying one-third of the daily recommended value for adults -- can help speed elimination and possibly promote weight loss; their natural sweetness may satisfy cravings for less wholesome foods.
Beneficial Vitamins and Minerals
A cup of fresh raspberries contains high levels of assorted vitamins and minerals needed for healthy body functions, including 186 mg of potassium, necessary for maintaining healthy blood pressure; 31 mg of calcium, needed for bone development and growth; and 167 combined mcg of lutein and zeaxanthin. This pair of carotinoids -- or plant pigments -- can help protect against macular degeneration, an eye disease that can cause loss of vision. The same cup of raspberries also offers up 26 mcg of folate, which can prevent neural tube defects in newborns.
Alleviate Arthritis
Raspberries can fight inflammatory conditions -- such as arthritis and gout -- in much the same way as aspirin and ibuprofen do: by turning off signals sent by COX-1s and COX-2s, the enzymes responsible for the body's inflammatory response. Researchers believe that anthocyanins -- the water-soluble plant pigments that give the berry its vivid color -- are responsible for its anti-inflammatory properties. Arthritis Today recommends blending raspberries with pure fruit juice and heating them to make a berry-infused, colorful and intriguing sauce for lean meat and chicken.
Antioxidant Benefits
Chemoprotective Benefits
As if raspberries' nutritive, antioxidant and anti-inflammatory powers weren't impressive enough, animal and test tube studies have shown that they may help prevent cancer. Ellagic acid, a phenolic compound, can kill certain types of cancer cells, including those of colon, esophageal, liver, lung, tongue and skin cancers. Quercetin is yet another effective anticarcinogen found in raspberries; studies support its ability to act against mammary cancers in rodents. In a clinical study published in 2010 in "Cancer Prevention Research," researchers found that black raspberry powder fed to mice for 12 weeks was highly effective in preventing intestinal tumors. The black raspberry powder inhibited tumor development by reducing inflammation.
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