It is best to complete the pruning of red and white currants as soon as possible. If you are dealing with a mature, well-established bush with lots of stems arising from just above ground level, you should aim to remove a few of the oldest stems each year, especially from the centre of the plant. This allows good air circulation in the summer when foliage is dense. Each selected old stem should be cut back to just above a bud. At the same time, weak and crossing stems can be removed. This simple method of pruning will let you keep the plant well-shaped, with stems that are not too overcrowded, while encouraging a continuous supply of young, healthy, fruit-bearing stems for future years. One of the most important general things to remember when pruning redcurrants, whether they are grown as bushes, or less commonly, as cordons or fans, is to remove any diseased branches, or branches that are showing early signs of disease.
Redcurrants are a good choice if you would like to grow soft fruit but know that your soil is fairly poor. Soil will still have to be well-prepared in advance of planting, and new plants will still need to be fed and mulched regularly, but redcurrants are not quite as hungry as blackcurrants. At the time of planting, it is worth while adding potash to the soil; redcurrants often show symptoms of potash deficiency which can cause the edges of leaves to appear discoloured and scorched. Redcurrants need sunshine if they are to thrive well, and a sheltered site is advisable because their long, slender branches snap easily in high winds. Ideally, young plants should be settled into the garden by the end of March, and if necessary, they should be supported by a couple of bamboo canes to help roots become established quickly.
The biggest problem with redcurrants is blackbirds. At harvest time in summer, blackbirds seek out redcurrant fruits. They will quickly strip them from the bush, hardly able to wait until the currants are fully ripe. The only way to combat this is to make sure that bushes are covered in a protective net. It is easier to use a single net that is large enough to cover a whole plant, rather than try to join up two or three nets. Buy a net now, or at least sometime soon, well in advance of June or July when the currants will be ripening. Make sure the net is in place in late spring or as soon as you see strings of pale, unripe fruits hanging from the branches. A net hung over four bamboo canes topped with inverted flower pots is the simplest method, but you must make sure it is carefully fastened down around the bottom of the plant. It is important to check beneath the net every day in case a marauding blackbird is awaiting release after having managed to sneak inside the net, eaten its fill, and then become trapped. There’s always one!