A blackberry isn't a berry, and it keeps a core raspberries lose
Botanically, a blackberry is a cluster of tiny stone fruits, not a berry at all. What separates it from a raspberry is the core: pick a raspberry and the central stem stays on the plant, leaving a hollow; pick a blackberry and the stem comes with it. Also, blackberries are red when they're green.
The name covers more than 375 species in the genus Rubus of the rose family, plus many hybrids. Many reproduce without fertilisation, a trick called apomixis, spawning swarms of near-identical microspecies that have long confused taxonomists, who often lump them into aggregates. Wild blackberries range across Europe, northwestern Africa, temperate Asia and the Americas. Each drupelet forms around its own fertilised ovule, so poor pollinator visits leave gaps and crumbly fruit.
The plant runs on a two-year cycle. A first-year cane, the primocane, can trail 3 to 6 metres without flowering; in its second year it becomes a floricane, stops lengthening, and sends out flowering side shoots. Thorns appear on both, and thornless varieties are a recent achievement. Canes root wherever their tips touch soil and suckers rise from the roots, so an unmanaged patch becomes a dense tangle that thrives in ditches and on roadsides. In Australia, Chile, New Zealand and the Pacific Northwest, the Himalayan and evergreen blackberries are declared noxious weeds.
Wildlife depends on them. Deer relish the leaves, some caterpillars feed on them, and red foxes, black bears, badgers and small birds eat the fruit and scatter the seeds. Harvests can be heavy: about 20,000 pounds per acre in a year is possible.
Most modern breeding happened in the United States. Judge James Harvey Logan crossed a blackberry with a raspberry in Santa Cruz, California, in 1880 to create the loganberry. An early thornless type from 1921 lost much of its flavour, but later US Department of Agriculture work produced smooth-stemmed varieties such as Black Diamond, now the leading cultivar planted in the Pacific Northwest, that suit machine picking. Mexico is the world's top producer, exporting almost all its crop to off-season markets, and Oregon leads US output, with about 19,300 tonnes in 2017.
Source: Blackberry
