Blackcurrant can damage both unopened and open flowers when the temperature falls below . The flowers at the base of the strig are more protected by the foliage and are less likely to be damaged. In midsummer the strigs of green fruit ripen to edible berries, very dark purple in colour, almost black, with glossy skins and persistent calyxes at the apex, each containing many seeds. An established bush can produce about 4.5 kilograms (10 pounds) of fruit each year. Plants from Northern Asia are sometimes distinguished as a separate variety, "Ribes nigrum" var. "sibiricum", of which "Ribes cyathiforme" is considered
Ribes thacherianum Ribes thacherianum Ribes thacherianum, with the common name Santa Cruz gooseberry, or Santa Cruz Island gooseberry, is a rare North American species of currant found only on one island off the coast of California. "Ribes thacherianum" is an erect shrub growing to a maximum height around 2.5 meters (over 8 feet). The stems are coated in soft light hairs and bristles, and many of the stem nodes bear hard spines. The leaves are 2 to 3 centimeters (0.8-1.2 inches) long and shallowly divided into five dully toothed lobes. The inflorescence is made up of one or two flowers. Each flower