Blackcurrant: planting, pruning and care

Description and botany

Blackcurrant bush blackcurrant, commonly called “blackcurrant” or “black currant bush”, is one of about 200 species of the genus Ribes which largely makes up the family Grossulariaceae. This family includes, depending on classification, the genera Itea, Escallonia and Ribes or Grossularia and Ribes. Its specific name nigrum simply means “black” in Latin, like the colour of its berries, as opposed to rubrum “red”, which denotes the redcurrant bearing red berries. The gooseberry bears the scientific name Ribes uva-crispa. Other non-European species and especially interspecific hybrids are classed among blackcurrants, such as Ribes americana, Ribes x nidigrolaria (casseille). Other species are grown for ornament, such as Ribes sanguineum, one of the first bushes to flower in spring with its generous clusters of pink flowers, or Ribes odoratum with yellow, delicately scented flowers and very aromatic foliage reminiscent of clove. Foliage generally takes beautiful autumn colours when climate suits it.

Blackcurrant bushes are deciduous native to Europe and temperate Asia, occupying cool woods from the Pyrenees to Central Asia. Cultivation began in the 16th century. Ribes all produce juicy berries that can be white, red, purple, green or black, generally edible even if flavour is not always remarkable. Shoots and fruits are sometimes armed with prickles but this is not the case for blackcurrant. The plant forms a vigorous, bushy shrub 1.2 to 2 m tall. When shoots are broken, a thick pith is noticeable. Buds are small and very acute, sometimes pecked by birds in winter.

Ribes nigrum – botanical illustration

Plant forms long branches adorned with short shoots that will bear flowers and fruits. Shrub reaches maturity in three years. Leaves, fruits and buds are intensely scented due to glands containing essential oils used in perfumery. Bark is smooth, glossy, reddish-brown.

Alternate leaves bear 3 to 5 crenate lobes and are attached to stems by a petiole pubescent almost as long as the lamina. Glabrous foliage, 6 to 10 cm long, is dark green, paler beneath, turning yellow in autumn before falling. It releases an aromatic scent when crushed and can be used to make herbal teas.

Flowering in April–May is rather discreet and appears as long pendulous clusters of campanulate yellowish flowers. Flowers are hermaphrodite but often require another compatible variety to fruit well. Breeding improvements have, however, produced self-fertile blackcurrant varieties. Insect pollination produces about two months later small globular black berries, roughly 1 cm in diameter. Berries retain the dried calyx at their tip. Harvest takes place between June and August depending on variety. Blackcurrant’s flavour rarely makes it enjoyable raw unless mixed with strawberries and raspberries. However the recent variety ‘Noiroma’ offers large fruits that are particularly sweet.

Extraction of essential oil from buds is used in perfumery while blackcurrant berries are mainly offered as processed products such as jellies, tarts, sorbets and syrups or liqueurs. Their acidity is tempered by sugar from raspberries or strawberries. Blackcurrant is Europe’s fruit richest in vitamin C (200 mg/100 g); it also contains iron, calcium, vitamins E, A and B and pigments of anthocyanins which are of interest in combating myopia, eye fatigue and skin ageing. Tannic acid, which gives its astringency, acts against cardiovascular diseases.

Main blackcurrant varieties

Early varieties

Late varieties

Blackcurrant Andega - Ribes nigrum

Bush with medium vigour, very productive and self-fertile, resistant to powdery mildew. Yellow bark provides a striking contrast with black berries tinged with pink. Flowering in late April is followed by a harvest in early July of attractive clusters of tasty, fleshy, tangy and aromatic berries.

• Flowering time May, June
• Height at maturity 1,50 m

See the product sheet

Blackcurrant Noir de Bourgogne - Ribes nigrum

Early variety producing long clusters of large fruits with a slight tang, well scented at full ripeness. This variety is fairly susceptible to powdery mildew and anthracnose. To ensure good pollination, plant with Cassissier Géant de Boskoop.

• Flowering time May, June
• Height at maturity 1,50 m

See the product sheet

Blackcurrant Perles d'Auvergne - Georges Delbard

Brand-new variety selected for strong disease resistance and very aromatic flavour. Fruits ideal for making jellies and liqueurs. Early and self-fertile.

• Flowering time May
• Height at maturity 1,20 m

See the product sheet

Blackcurrant Giant Boskoop - Ribes nigrum

Early variety to harvest from early July but with late flowering that avoids spring frosts. Vigorous bush resistant to powdery mildew, moderately productive, with very aromatic foliage. Produces large tangy fruits with an appreciated scent at full ripeness. Good pollinator of 'Noir de Bourgogne'.

• Flowering time May, June
• Height at maturity 1,30 m

See the product sheet

Blackcurrant Wellington - Ribes nigrum

Early, vigorous variety producing attractive clusters of large, slightly tart black fruits with excellent-quality flesh. Early flowering and very good yields.

• Flowering time May
• Height at maturity 1,50 m

See the product sheet

Blackcurrant Black Down - Ribes nigrum

Late variety (late July) producing multiple short clusters of black-violet colour with good eating quality. Early flowering from April may make it vulnerable to spring frosts. Self-fertile variety offering good yields and low susceptibility to rust.

• Flowering time May
• Height at maturity 1,50 m

See the product sheet

Blackcurrant Titania - Ribes nigrum

New late, self-fertile variety with good productivity, producing attractive clusters of large, mildly tart berries. Harvest from late July.

• Flowering time May
• Height at maturity 1,50 m

See the product sheet

Planting

Where to plant blackcurrant?

Blackcurrant is of excellent hardiness (-25 °C) and prefers regions north of the Loire or mid-mountain areas. However it is sensitive to prolonged cold between 1 and 5 °C which can cause fruit drop due to poor fertilization. In the south, give it a cool, partially shaded spot rather than full sun.

It tolerates ordinary, deep, rather humus-bearing soil without too much lime, cool in summer but well drained, although it will tolerate heavy clay soils.

Choose a position out of direct sun, or in partial shade, in a place sheltered from strong winds. Blackcurrant dislikes heat and drought.

If possible, plant several varieties of blackcurrant alternately to encourage pollination even for self-fertile varieties. Allow one pollinator for every four young plants.

When to plant?

Planting is recommended between October and March while foliage is absent, avoiding frosty periods.

How to plant?

This plant is very easy to grow, especially if placed in cool conditions sheltered from wind and burning sun. Allow spacing of 1.50 to 1.80 m if forming a hedge.

• For a young plant in a container, plunge the rootball into a bucket of water to thoroughly moisten it or, if it is a bare roots young plant, trim damaged roots cleanly then coat them with pralin or, if unavailable, with mud.
• Using a spade, dig a hole 30 cm in all directions, avoiding smoothing the sides.
• Work the soil, removing stones and unwanted weeds,
• Add a generous amount of well-rotted organic matter (potting compost, compost…). In poor soil, add crushed horn (rich in nitrogen) and a base fertiliser (rich in phosphorus and potassium). If soil is chalky, add turf and plan a mulch of acidic materials (pine needles or pine bark…).
• Bury the blackcurrant’s collar by 5 cm to encourage the production of new shoots, then backfill with soil forming a saucer.
• Pour a full watering can to settle the soil and drive out air bubbles.
• Remember to cut back the clump to 2–3 buds if this was not done at the nursery.

In a pot: place at the bottom of a deep pot a layer of gravel or clay pebbles to improve drainage.

Fill the pot with a mixture of potting compost, garden soil and compost.

Pruning, care, potential diseases

Pruning blackcurrant bush

The aim is to obtain then maintain about a dozen productive shoots per plant. To do this, cut back stems to 2–3 buds in year of planting. Renewal of oldest shoots (5–6 years) begins after 3 years and continues for more than 15 years for optimal production. Carry out in winter or just after harvest.

For more information, see this sheet: Pruning gooseberry and blackcurrant

Care

• Apply an organic fertiliser each year at start of growth to support fruit production and plant health.
• Keep soil cool with regular watering, especially in spring to prevent rust.
• Low temperatures between 1 and 5°C affect the fertilization of flowers at flowering and can cause fruit drop. Install winter fleece if needed during cool nights.
• Install bird netting before fruits redden or, better still, offer birds a bowl of water.
• In autumn, remove dry or spotted leaves.

This accommodating bush is not very susceptible to diseases. It does have a few enemies, such as aphids, scale insects and mites, whose overwintering stages should be destroyed by a winter treatment. The clearwing is a white caterpillar that bores into blackcurrant stems between June and October. Cut and burn affected shoots. If rust (orange pustules on underside of leaves) appears, spray a fungicidal treatment such as horsetail decoction. Avoid five-needle pines (Weymouth pine) within 1 km and sedges (Carex) that transmit this disease. L’anthracnose is signalled in June–July by angular white spots rimmed with reddish-brown associated with premature leaf drop or with drying out of clusters. Collect and burn fallen leaves, apply a fungicidal copper treatment at end of flowering, again 15 days later, then a third after harvest.

Abnormally swollen buds that dry out or produce plicate leaves indicate attack by currant bud mite, which can transmit blackcurrant reversion virus, incurable. Remove and burn affected buds. Uproot plant if too weakened.

If hungry birds in winter attack buds, offer them seeds.

Installing protective netting

Harvest and storage

Harvesting blackcurrants

• Pick the whole cluster after checking that the berries at the base, which ripen later, are ripe, because fruits must have reached perfect ripeness. As soon as the first fruits begin to fall, act quickly. Harvest takes place late June–July, even August–early September with late varieties such as Tsema or Jet, or if the climate is cold. A mature plant yields between 2 and 4 kg of fruit.
• In the morning or late afternoon, when there is no rain, comb clusters or berries into a basket lined with a tea towel and place them quickly in a cool place.
• Rinse them quickly under fresh water before eating, freezing them, well spreading on a tray, or processing them.

Storing blackcurrants

• Blackcurrants can be kept in the refrigerator’s vegetable drawer for up to one week. They can then be eaten in salads, used to decorate cakes or ice cream. They can be paired with meats such as beef or game, or used to make muffins, tarts…
• Turning them into jams, jellies, juices, coulis, ice creams or syrups is, of course, essential.
• Don’t forget to use blackcurrant bush foliage to flavour wines and liqueurs after maceration.

Propagation: how to propagate blackcurrant

Propagation by cuttings is carried out from late August to October or in March.

Propagation by cuttings

• Take cuttings about 20 cm long from semi-ripe or ripe shoots depending on season chosen, each with at least 4 buds.
• Place cuttings directly in their final position in groups of three or in a small trench, in light, fresh soil and partial shade. Leave only two buds exposed.
• Keep soil cool and moist during summer.
• Optionally transplant rooted young plants after one year.

Uses and associations

In garden, create a small edible hedge by mixing blackcurrant bushes, redcurrant bushes and raspberry plants, for example along edge of vegetable plot, or plant blackcurrant bush within a border of flowering bushes or at back of a perennial border made up of Japanese anemones, Hosta or Heuchera.

Another idea for association: blackcurrant bush and redcurrant bush accompanied by some strawberry plants at their feet. You can add herbs (thyme, sage…) which attract pollinators that will also pollinate your fruit bushes

Blackcurrant bush adapts well to growing in a deep pot but must be the only plant in that pot.