Culture
Best grown in organically rich, slightly acidic, moist but well-drained soils in full sun to part shade. Intolerant of wet soils which can cause root rot. Prefers a loose textured soil. Raised beds should be considered in areas with heavy clay soils. Best fruiting generally occurs in climates with cool summers (high summer heat may stunt plants). Plants are self-fruitful. Canes are biennial, meaning that the summer fruit crop appears in the second year on old wood (vegetative canes that have overwintered from the prior year). Accordingly, each year, mature summer-bearing raspberries should be pruned as follows: (1) Remove canes that have fruited immediately after fruit is harvested, leaving the new vegetative (non-fruiting) canes to overwinter. Also remove at this time any non-fruiting canes that exhibit weakness or disease or are growing in strange directions. (2) In late winter, remove any canes damaged by winter and thin the remaining canes as needed, leaving only healthy, well-spaced canes. In addition, the height of all canes, or at least the longer ones, may be reduced at this time by up to 6” so as to remove the tips which produce the smallest fruit and to help the canes remain self-supporting (i.e., helps keep fruit off the ground).
Noteworthy Characteristics
Raspberries are aggregate fruited brambles native to temperate regions around the world. The biennial canes emerge from a perennial rootstock and can take on a sprawling to semi-erect habit. Many raspberry cultivars available today are hybrids of multiple species in the genus Rubus, with the two most common being R. idaeus (red raspberry) and R. occidentalis (black raspberry). Raspberries can be distinguished from blackberries by certain characteristics of their aggregate fruits. When raspberries are picked off the canes, the receptacle (central attachment point for the fruiting body) is left behind, creating a hollow space inside the aggregate fruit. The drupelets (small, individual fruits that make up the aggregate fruit) of raspberries have small hairs while the drupelets of blackberries are smooth. Raspberry cultivars are mainly characterized by their fruiting color and habit, as well as whether the canes bear thorns or are considered thornless. Red, black, yellow, and purple raspberries are all commercially available. Cultivars that produce a single crop on only two year old canes are called floricanes. "Everbearing" or primocane varieties will produce fruit on two year old canes as well as a small, late crop on new canes.
Genus name is the Latin name for brambles (blackberry and raspberry).
‘Bristol’ (introduced in 1934) is a mid-season black raspberry cultivar that is noted for its excellent flavor. One berry crop each year is produced in early summer. Clusters of white, 5-petaled, rose-like flowers with yellow anthers bloom in spring (May). Flowers give way to an abundant crop of glossy, non-seedy black raspberries of excellent eating quality. Fruit matures in late June to early July in the St. Louis area. Berries may be eaten fresh or used in jams and jellies. Pinnate green leaves. Commercially, black raspberry production has declined in the eastern U.S. in large part because of disease susceptible cultivars and low fruit yields per acre. Black raspberries can be difficult to grow well in the State of Missouri as well as in areas south of Missouri.
Problems
Anthracnose, botrytis, spur blight, root rot, leaf spot and other fungal diseases can cause serious problems that may necessitate chemical treatments. Watch for verticillium and/or bluestem wilt and raspberry mosaic disease complex. Cane borers and crown bores are potentially serious insect pests. Aphids can be troublesome.
Uses
Although the flowers are quite attractive, this raspberry is grown as a fruit crop and is generally not considered appropriate for ornamental use.