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 marshallii Ribes marshallii Ribes marshallii is a North American species of currant known by the common names Hupa gooseberry and Marshall's gooseberry. It is endemic to the Klamath Mountains of southern Oregon and northern California. "Ribes marshallii" grows in mountain coniferous forests. It is a shrub producing arching stems 1 to 2 meters (40-80 inches) long which may root at the tip when it reaches moist substrate. Nodes on the stem bear three spines each up to a centimeter (0.4 inch) long. The lightly hairy leaves are roughly three centimeters (1.2 inches) long and are divided into a few widely toothed