Black Currants & Red Currants – Ribes
Of the three kinds of currants, black currants derived from Ribes nigrum are grown. more commonly than red currants (derived from the intercrossing of three Ribes species) or white currants (derived from red currants). All three are self-fertile, fruit prolifically and take up only a relatively small area. Red and white currants withstand drought better than black currents and are less greedy for nitrogen. Otherwise, their requirements are very similar.
Black currants are in season from July to early September, fruiting on the previous season’s shoots. Red and white currants ripen from late June to late July and fruit on spurs formed on the old wood.
The modern method of planting black currants is to insert three cuttings 10cm (4in) deep at each planting position and allow them to fruit in situ. Plant at 2 x m (6 x 3ft) intervals. Cuttings 30cm (12in) long, are taken in the autumn from well-ripened shoots of the current season’s growth—it is unnecessary to make the cuts directly below the nodes as the cuttings root readily wherever the cuts are made.
Alternatively, plant one to two-year old bushes between October and mid-March, the earlier the better. The soil should be dug deeply prior to planting and have 51kg (lcwt) of well-rotted farmyard manure dug in every 10 sq m (10 sq yd). Do not allow the fibrous roots to become dry while awaiting planting;
heel them in until planting can be carried out. The roots should not have more than 5cm (2in) of soil above them when planted in their permanent positions.
Cuttings rooted in situ can be allowed to fruit the first season but transplanted one-year-old bushes should be pruned to help them recover from the transplanting check and induce strong growth, by shortening the shoots to four buds.
Prune established black currant bushes as soon as their crop is harvested. Remove about a third of the older branches to maintain vigor and to induce sucker shoots to form below ground. Retain a good supply of last year’s shoots, spaced evenly over the bush. Mulch the bushes in April with hop manure, matured deep litter poultry manure or decayed farmyard manure.
Feed black currants in the spring with 56g (2oz) per sq m (sq yd) of sulphate of ammonia or Nitro-chalk and in the autumn with 28g (loz) per sq m (sq yd) of sulphate of potash. Red and white currants manage with 28g (loz) of sulphate of ammonia per sq m (sq yd) in the spring and the same amount of potash in the autumn.
Generally, red and white currant bushes are grown with a short leg, 10-13cm (4-5in) in length, sucker growths being removed; on dry gravel soils, die back may be severe and a multi-stemmed bush may be more practical. Bushes with a leg are obtained by first removing the buds from the bottom half of each cutting before insertion.
Single or double cordon red or white currants, planted against a wall, give extra-large berries and are easily netted against birds. Plant bushes 1.5 x 1.5m (5 x 5ft), single cordons 0.3m (lft) apart in the row, double cordons, 0.5m (lift) apart in the row; rows 1.3m (4ft) apart.
Prune red currants in the winter by shortening the leading shoots by a third and the sideshoots to two or three buds. Summer pruning in July promotes fruit bud formation. Shorten the sideshoots to five leaves; leave the leading shoots unpruned.