Black raspberry (Rubus occidentalis)

Rubus occidentalis or black raspberry is native to North America, Fruit flavor is stronger and the fruit is generally smaller than that of red raspberry. Black raspberries are not as winter-hardy as red ones, but tend to tolerate more summer heat. They also are more prone to viral and fungal disease and have stiffer thorns. The berries are seedy but have a very intense flavor. They are good eaten fresh or in preserves.

Primocanes are produced from buds at the base of floricanes at the crown or from buds on roots in red raspberry. Black raspberries only produce new primocanes from buds on the crown.

They exhibit high antioxidant activities due in part, to their high levels of anthocyanins, ellagitannins and other phenols. Black raspberries have four major anthocyanins: cyanidin 3-glucoside, cyaniding 3-rutinoside, cyanidin 3-sambubioside and cyanidin 3-xylosylrutinoside.

The black raspberries have a much greater total anthocyanin concentration compared to red raspberry. Black raspberries have been investigated extensively for their ability to prevent cancer in rodents and potentially in humans.
Black raspberry (Rubus occidentalis)

Purple raspberries

Also known as purple-cane hybrids, purple raspberries are domesticated cultivars with a mixture of red and black raspberry genes.

Most purple varieties are similar in flavor to the raspberries; however some purple varieties produce canes, and others share the growth habit of the black raspberries.

The canes are generally more winter hardy than the black parents. They tend to be very spiny and productive with large, intensely flavored berries.

The canes are prickly but not bristly, have an arching habit, and root at the tip. Leaves are morphologically variable and the flowering branches glabrous. Fruits are dark red to purple.

The purple raspberry cultivar ‘Royal’ is now widely grown in northeast China, where it is highly productive, amenable to cane burying for winter an harvested at the early stages of ripeness when it can be sold as ‘red raspberry’.
Purple raspberries