Cultivated blackberries are normally more than 3 cm long and around 2.5 cm or more in diameter. They have a sweet-tart flavour, and are usually very juicy.
Wild blackberries are characterized by their smaller size. They are less than 3 cm long and less than 2cm in diameter. They tend to have a more tart flavour, and are sometimes described as “crunchy” because they have less juice around their seeds.