Currant

Broadcast about a quarter to a third of a pound of 10-10-10 or 12-12-12 per plant on the soil surface each spring, spread out toward the drip line rather than piled against the crown. Well-rotted stable manure works just as well and currants respond strongly to it. Keep young plants on a lighter ration. Currants fruit on one, two and three year old wood, so every year you prune away a share of the bush and the plant has to fund a fresh set of vigorous canes to replace it. Nitrogen is what pays for those canes, and a starved bush quietly stops renewing itself.

Before growth starts, remove old unproductive canes and keep a mix of one two and three-year wood. Currants bear best on younger wood, and open bushes dry faster after rain.

While you are pruning in spring, look for canes whose leaves yellow or whose tips wilt and die back rather than leafing out. Cut each of those canes right out at the base and destroy the wood - burn it or bin it, do not chip it into your mulch. Cut sickly canes out as soon as you notice them rather than waiting for next winter. The borer larva spends the winter tunneling the pith inside the cane, and the adult clearwing moth chews its way out in early summer to lay eggs on the neighboring canes. A cane that wilts is telling you a moth is developing inside it, and taking that cane out before the flight breaks the generation.

Open the bush up: prune for airflow, site it in sun, and cut out infected shoots. Choose resistant cultivars when replanting. Sulfur is labelled on currants for leaf spots and can be used up to the day of harvest, but it is not a mildew material. The extension consensus for Ribes powdery mildew is cultural, not chemical - the fungus is managed by light and air movement rather than a spray programme.

As the buds break and the first leaves open, turn a few of them over and look. If aphids are already feeding, spray insecticidal soap or an ultrafine horticultural oil, aimed up into the undersides of the leaves - that is the only place the spray will reach them. The overwintering eggs hatch just as the first leaves unfold, and the aphids feed underneath and blister and curl the terminal leaves around themselves. Once a leaf has curled shut, no spray gets to the insects inside it, so the open window is genuinely only a few days wide.

Currants flower earlier in spring than almost anything else in the fruit garden, so keep an eye on overnight lows once the blossom opens and throw a row cover or old sheet over the bush if a hard frost is forecast. When siting a new plant, stay out of low-lying frost pockets, and keep it off the heat-collecting south side of a building - currants want the cool spot, not the warm one. Blooming that early means the flowers are open while hard frosts are still in play, and cold air pools in low ground exactly when the bush is most exposed. A warm south wall makes it worse by pulling the bloom forward into the risk.

After the petals drop, part the bush and inspect the lowest, innermost leaves. If you find pale-then-greenish larvae with black spots and black heads chewing small holes in the leaf centers and notching the margins, spray spinosad or insecticidal soap. If there are only a few, hand-picking is enough. Look again in June or July for a second generation. This is a sawfly larva, and the female lays her eggs along the midribs on the undersides of the lowest leaves. The brood starts deep in the bush where you do not see it and eats outward, and a heavy first generation can strip a mature bush bare - which costs you next year's fruiting canes as much as this year's crop.

Give the bush one to two inches of water a week from fruit set right through until you have harvested. Use drip irrigation or a soaker hose at ground level rather than an overhead sprinkler. The berries do most of their swelling in the weeks just before they ripen, and a dry spell in that window leaves you small, seedy fruit that no later watering will fix. Watering at ground level also keeps the canopy dry, which matters because the leaf spot and mildew fungi need wet foliage to infect.

Red and white currants color up well before they are sweet - the fruit holds well on the bush, so give it two or three more weeks after it turns to build flavor and sweetness. Then snap off the entire cluster by its stem instead of stripping berries off one at a time. A mature bush should give you three to ten pounds, depending on cultivar. Currant skins are thin and tear where the berry joins the strig, and a torn berry bleeds juice and molds within a day. Taking the whole cluster keeps every berry intact, and it is far faster besides.

Once the leaves have dropped, rake out and destroy the ones showing brown or purplish spotting, then top the ring back up with a few inches of wood chips, pine needles or compost. Pull the mulch back an inch or two so it is not banked against the canes. Anthracnose overwinters on last year's fallen leaves lying under the bush, and next spring's rain splashes those spores straight back up onto the new foliage. Clearing the worst litter and burying the rest under fresh mulch cuts the inoculum before it can start the cycle over.