How to Grow Jostaberries
Jostaberries are hybrid of the black currant (Ribes Nigrum), the North American coastal black gooseberry (Ribes Divaricatum) and the European gooseberry (Ribes Uva-Crispa).
Almost black berries are smaller than a gooseberries and a bit larger than a black currants with a taste between a gooseberry and a blackcurrant. Fruits are edible and often cooked. Like blackcurrants, jostaberry fruits freeze well.
When growing in small gardens, keep in mind that the ripe fruits can be kept on the bush in good condition through entire late summer. However, birds like jostaberries and fruits must be protected by nets.
Jostaberry grows to a maximum height of about 2 m and is resistant to a number of common diseases afflicting many other berries. Jostaberry is resistant to diseases like blackcurrant leaf spot, American gooseberry mildew, white pine blister rust, big bud gall mite, etc.
In areas where diseases prevent successful cultivation of gooseberries and similar plants, jostaberries can be used as replacement.
Even is one doesn't have issues with gooseberries, currants and other berries, feel free to plant few jostaberries.
Propagation is similar to the propagation of gooseberries - seeds can be used, but mostly jostaberry is propagated using cuttings. In late winter or early spring, 20-25cm (8-10 inches) cuttings are taken from plants and planted into the flower pots, filled with good rich soil that is kept wet. Rooting hormone can be used, but good results are achieved even without it. Actually, this method can be used almost year long, but late winter and early spring are the best time for propagation using cuttings.
If one needs just a few plants, it is perhaps the best option to buy plants in local garden centers ready for transplanting on permanent location.
Jostaberries should be planted on rich, well drained, slightly acidic soil. They prefer sunny positions, protected from strong winds. Jostaberries tolerate colder climate, however, late spring frost can damage the flowers.
In late autumn, add aged manure and some compost/humus. In later winter, add again some aged manure, compost/humus and balanced NPK fertilizer, preferably with gradual release of nutrients. Jostaberries are very vigorous plants, so excess nutrients, especially nitrogen can make them big, but weak.
Jostaberries produce fruit on one and two year old canes, but also on older wood. However, to keep the bush 'open', prune regularly in late winter, before the plants start to grow:
- remove anything that is broken, ill or crosses with other branches,
- prune half of young shoots to about 15cm (6 inches) above the ground and leave the other new shoots,
- prune one-third of the older, woody growth to within 2-3cm (1 inch) above the ground.
Note: jostaberries are pruned in order to let the sunlight pass through the bush (prevents disease), to stimulate fruit production and to ease the harvest.
One more thing - unlike gooseberries, jostaberries don't have thorns! :)