Blackberry and raspberry fruit produce an aggregate fruit and are derived from many ovaries from a single flower. The major difference between blackberries and raspberries is that when blackberry fruit are consumed the receptacle of the inflorescence (known as a torus) is also consumed. By contrast, raspberries when picked ripe for consumption will have a hollow center since the receptacle remains on the cane. Raspberries are not generally recommended for the southeastern United States and will be discussed only very briefly. 'Dorman Red' is the only raspberry cultivar recommended for trial in Florida when grown as a perennial crop; however, berry flavor is poor to fair. 'Heritage' raspberry has been grown as an annual crop during the winter in the southern parts of the state after it receives its chilling requirement.
Blackberry fruit is borne on the current year's growth with usually 10 to 20 flowers per cluster. Blackberries and raspberries are an aggregate fruit with individual pistils which form druplets. To obtain a large well formed berry most of the individual pistils in an inflorescence should be pollinated. Inadequate pollination results in smaller or imperfect fruit since not all seeds and druplets are formed. Blackberries range from completely self-fruitful to completely self-unfruitful. Most erect blackberries are fruitful yet trailing cultivars often require cross pollination. It is often reported that cross pollination results in highest yields. Several different blackberry cultivars should be planted together to insure cross pollination particularly if wild blackberries are not in the vicinity. Blackberries flowers produce nectar and pollen that attract bees which serve as pollinators. Honey derived from blackberry flowers is reported to be light in color with good flavor.
The blackberry is an edible fruit produced by any of several species in the Rubus genus of the Rosaceae family. The fruit is not a true berry; botanically it is termed an aggregate fruit, composed of small drupelets. The plants typically have biennial canes and perennial roots. Blackberries and raspberries are also called caneberries or brambles. It is a widespread, and well known group of over 375 species, many of which are closely related apomictic microspecies native throughout the temperate northern hemisphere and South America.
In its first year, a new stem, the primocane, grows vigorously to its full length of 3–6 m (in some cases, up to 9 m), arching or trailing along the ground and bearing large palmately compound leaves with five or seven leaflets; it does not produce any flowers. In its second year, the cane becomes a floricane and the stem does not grow longer, but the lateral buds break to produce flowering laterals (which have smaller leaves with three or five leaflets). First and second year shoots usually have numerous short curved very sharp prickles that are often erroneously called thorns. Prickle-free cultivars have been developed. Recently the University of Arkansas has developed primocane fruiting blackberries that grow and flower on first year growth much as the primocane-fruiting (also called fall bearing or everbearing) red raspberries do.