Raspberry

Raspberry is the name given to two plant species in the genus Rubus, Rubus idaeus (red raspberry) and Rubus occidentalis (black raspberry) grown for their edible fruit. Raspberry plants have perennial root systems and biennial stems which are known as canes. The canes are woody, erect and shrub-like and generally undergo a period of growth one year and fruit production the next although primocane varieties exist that produce fruit in the first year. The canes may possess spines. Raspberry plants produce white or pink flowers with five petals which are surrounded by green sepals. After the plant has been pollinated, an aggregate berry is produced which consists of numerous druplets which are held together into the familiar raspberry fruit by tiny hairs. Raspberry canes can grow from 0.5 to in excess of 2 m (1.6–6.6 ft) in height and red raspberry will produce a commercial yield of fruit for 16–20 years, while black raspberry has a shorter lifespan and will produce for 4–8 years. Red raspberry may also be referred to as European raspberry, red garden raspberry or hindberry, while black raspberry may be referred to as blackcap raspberry and may have originated in the Ide mountains of Turkey.


Raspberries are primarily consumed as a fresh fruit or may be processed into jams, jellies, juices and pulp.


Requirements Raspberry plants grow best in regions with cool summers and relatively mild winters. The plants are sensitive to high temperatures and grow best when daytime temperatures are around 25°C (77°F). Raspberries are best suited to well-draining sandy loams, rich in organic matter and have a pH between 5.5 and 6.5. Drainage it critical in raspberry propagation as the plants are susceptible to root rot. Plants require full sunlight and should not be planted in low lying areas where water may build up. Raspberries also require a post support system or trellis to support the weight of the fruit on the canes. Raspberry canes are biennial and produce fruit in the second year of growth. Canes in their first year of growth are called primocanes and those in the second year of growth are called fruiting canes or floricanes. The young canes are green in color, whereas the older floricanes are tougher and have a woody covering making them easy to tell apart. Preparation Soil may need prepared up to two years in advance of planting if major amendments are required. Acidic soil can be amended with lime to bring the pH up to a level suitable for raspberries. Organic content can be increased by planting a cover crop or by the addition of manure or compost. Avoid planting raspberries where peppers, eggplant, tomatoes or potatoes have been grown previously as these plants are host to Verticillium fungi which can cause root rot in raspberries. Choose a raspberry variety which is suited to your region. Red raspberries tend to be the most cold hardy, whereas black or yellow varieties are more sensitive. Planting and trellising Many raspberry varieties are very vigorous and using a support system such as a trellis will help to protect the canes from wind damage while also supporting the weight of the fruit crop. The trellis should be constructed before or at planting to avoid damaging the young plants after they are in the ground. The traditional method of supporting red raspberry canes is a post and wire system. This method involves running two wires about 60 cm (2 ft) apart vertically between wooden posts staked into the ground. The lower wire should be positioned 90 cm (3 ft) from the ground and the upper 1.5 m (5 ft) from the ground. The raspberry canes can then be tied to the wires. A second option is a T-trellis which is similar to the post and wire but the vertical wooden posts each have two cross bars to attach the wire. Two sets of wires run parallel to one another, one above the other. The vertical posts should be spaced 3.6–4.6 m (12-15 ft) apart with the lower wire positioned 90 cm (3 ft) from the ground and the upper 1.5 m (5 ft) from the ground. Raspberry plants in the home garden are usually grown from bare root plants or from tissue-cultured plants and should be planted in early Spring when the danger of any severe frosts has passed. The plants are usually planted in a row and the suckers will fill in the spaces to produce a hedge. Plant approximately 70 cm (27.5 in) apart, allowing 2.4–3 m (8–10 ft) between rows. Pruning Allow the raspberry plants to fill in the row to a width of about 30–38 cm (12–15 in) during the course of the growing season. Remove any suckers which are produced outwith this row. After harvest, cut the fruited canes of summer-fruiting varieties to ground level. Select 6–8 of the strongest young canes on each plant and tie them to the supporting wires so that they are spaced 8–10 cm (3–4 in) apart. Cut all of the canes of Autumn fruiting varieties to ground level after harvest. Cut back canes as needed in the summer if required to prevent crowding.


CABI Crop Protection Compendium. (2014). Rubus idaeus (raspberry) datasheet. Available at: http://www.cabi.org/cpc/datasheet/48002. [Accessed 06 April 15]. Paid subscription required. Ellis, M. A. & Converse, R. H. (Eds.) 1991. Compendium of raspberry and blackberry diseases and insects. American Phytopathological Society. APS Press. Strick, B. C. (2008). growing raspberries in the home garden. Oregon State University Extension. Available at: http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/18936/ec1306.pdf. [Accessed 06 April 15]. Free to access.