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 lacustre planting of any currant and gooseberry species is prohibited. Ribes lacustre The shrub Ribes lacustre is known by the common names prickly currant, black swamp gooseberry, and black gooseberry. It is widely distributed, from California to Alaska and across North America east to Pennsylvania and Newfoundland, and south as far as New Mexico. The shrub grows erect to spreading, 0.5–2 m. Clusters of reddish to maroon flowers bloom in spring. The fruit consists of dark purple berries 6–8 mm long. It blooms in April through August and may be found in low-elevation forests to the subalpine. Outside its native range,