BlackcurrantRibes nigrum

The blackcurrant is not grafted: it is always planted as a bush on its own roots, which explains its longevity and how easily it renews itself. The Scottish Ben varieties were bred for cool, rainy climates like ours; Ben Sarek stays compact, around 1.2 m, ideal in a small garden, while Ben Lomond and Ben Connan reach 1.5 m. Titania, from Sweden, is very vigorous and resists rust well. Prefer a certified two-year-old plant, with two or three stems, to a cutting from a neighbour, often carrying the big bud mite and reversion virus.

The blackcurrant flowers early, from mid-April, and its flowers drop below -2 °C: avoid dips in the ground and sloping garden bottoms where cold air collects, and prefer an open position sheltered from the east wind. Full sun gives the sweetest berries; light partial shade is tolerated and even delays flowering, which is no bad thing here. Leave 1.5 m on each side for access and laying a net. Do not plant near a Weymouth pine, the alternate host of blackcurrant rust.

The blackcurrant is the hungriest of the soft fruits: prepare a pit 60 cm square and 40 cm deep, loosening the bottom without bringing it up. Mix into the excavated soil a third of mature compost and a good spadeful of well-rotted manure, plus a handful of hoof and horn that will feed slowly. The soil must stay moist without suffocating: in heavy clay, raise the planting slightly on a small 10 cm mound rather than digging a hole that would hold water. A pH close to 6 suits it.

From November to March, outside frosty spells, plant bare-rooted after soaking the roots for an hour in water. Set the crown 5 cm lower than in the nursery, because the blackcurrant must constantly send up new stems from the stool; this deep planting is the key to a bush that renews itself. Fill in with the enriched mix, firm, water with ten litres. Then cut all the stems back to two or three buds above the ground: it is hard to do, but the shrub comes back vigorously in spring with six to eight new stems. Mulch 10 cm deep.

A blackcurrant in a container is possible but less convincing than a redcurrant: the plant needs to renew its stems from the base, which a pot limits. Choose Ben Sarek, the most compact, in a container of at least 50 litres, filled with a compost-rich mix. Water generously from May to July, as the broad foliage transpires a great deal, and top-dress with compost each spring. Prune harder than in open ground, to five or six stems. Expect a harvest of one to two kilos and a replacement of the plant about every eight years.

The most common is not cutting the plant back at planting, for fear of losing a year: you get a three-stemmed shrub that stays puny. The second is waiting for the end of the harvest to realise that the flowers froze: a fleece laid over the shrub on a clear April night saves the season. You also see blackcurrants planted in dry, sandy soil, without mulch, that lose their leaves in August. Finally, do not take over an old plant from a neighbour's garden: the swollen buds of the big bud mite spread within three years.

The blackcurrant has large leaves and spreading roots: it suffers quickly in June when the wind dries the soil. For the first two summers, water every week in dry weather, ten to fifteen litres at the base, without wetting the foliage so as not to encourage powdery mildew. The decisive period runs from fruit set to the swelling of the berries, from mid-May to the end of June. An extra watering in early August supports the formation of next year's fruit buds. Mature and well mulched, the shrub only asks for water during prolonged heatwaves.

The blackcurrant is the only soft fruit that tolerates and appreciates an annual dressing of manure: in March, spread under the mulch a barrowload of rotted manure or mature compost for three shrubs, topped up with a handful of sieved wood ash for potash. Then renew a 10 cm mulch of wood chippings or dead leaves, which will keep the soil cool and avoid any hoeing near the shallow roots. A spray of diluted nettle liquid in April gives young plants a boost. Avoid any feeding after July.

The blackcurrant fruits mainly on one-year-old wood, a little on two-year-old wood, hardly at all beyond. Formation is simple: after the planting cut-back, let it grow without pruning for two winters. From the third year, every winter, cut to ground level the quarter of stems that are oldest, with dark, branched bark, along with prostrate or spindly stems, to keep ten to twelve stems of which a third are the current year's shoots. Never shorten the vigorous shoots from the base, they carry the next harvest. Burn any wood carrying swollen buds.

The big bud mite, a tiny mite that swells the buds into round balls, is spotted in winter: pick off and burn every suspect bud, and grub out a plant with more than a third of its buds affected. Powdery mildew whitens the young shoots in June in warm, humid weather; the Ben varieties resist it, otherwise spray wettable sulphur or diluted milk at the first sign of felting. Rust, as orange spots under the leaves, disappears once pines are kept at a distance and fallen leaves are gathered up. Blackbirds are dealt with by a net laid as soon as the berries blacken.

In January, prune and inspect the buds. In March, manure and mulch; harvest a few buds for a maceration if you like. In April, watch for frosts and cover on clear nights. In May, water if the month is dry, and watch for powdery mildew on the young shoots. In June, lay the net and spot the first black berries at the base of the strings. Harvest in July in two or three passes. In August, water one last time and pick a few leaves to dry. In autumn, gather fallen leaves if rust has shown itself.

Beyond the basics, one detail changes everything: the strings on the same stem do not ripen together, and a berry that has been black for four or five days is sweeter than one freshly blackened. For crème de cassis or jelly, a single harvest when three quarters of the berries are black is fine; for eating fresh, go through three times. Handle gently, as the berry bursts and stains. Freeze on a tray then in bags; frozen berries strip off one-handed. The blackcurrant loses none of its fragrance in the freezer, unlike the strawberry.