Gadenin日本語Get the appThe loop the whole year turns on
Everything in the blackcurrant calendar serves a single mechanism. Wood grown this summer carries next summer's heaviest crop. So the growing season is about pushing out strong basal shoots and protecting them, and the dormant season is about removing the stems that have already had their turn. Get that loop right and the bush crops fully for fifteen years or more; break it in any one season and you feel it the following year rather than this one.
That delay is why keeping notes matters more here than on an annual vegetable. A poor crop this summer usually has its cause in what happened last summer, and only a record will tell you which.
| Season | Main job | What it is for |
|---|---|---|
| Late dormant season | Feed, mulch, remove swollen buds | Sets up the growth that becomes next year's fruiting wood |
| Bud burst to flowering | Watch for frost, keep weeds down | The flowers are the crop; frost at this point ends it |
| Fruit set to coloring | Water steadily, net the bushes | Berry size and keeping the crop from birds |
| Picking | Take whole strigs over two or three passes | Fruit ripens along the strig, not all at once |
| After harvest | Water, mulch, remove the net | New shoots are still extending and need moisture |
| Leaf fall to midwinter | Renewal prune, clear leaf litter | Removes the oldest third and the disease carried on old leaves |
Dormant season
This is the busiest part of the year for the gardener and the quietest for the plant. Prune once the leaves are down: take out about a third of the stems, always the oldest and darkest, cutting them flush at ground level. Late in the dormant season is a good time to do it, because by then the buds swollen by gall mite are obvious and you can bias your removals towards the affected stems.
Go over every bush bud by bud afterwards and pick off any remaining swollen buds. Burn or bin them and the prunings; do not shred them back under the bushes. Rake every fallen leaf out of the middle of the stool, because leaf spot overwinters there and reinfects the new leaves in spring.
Towards the end of dormancy, as the buds begin to move, spread a nitrogen-rich general fertilizer over the root area and follow it with a thick mulch of well-rotted manure or compost. This is also the window for planting new bushes and for taking hardwood cuttings from healthy, unaffected wood.
- Prune out the oldest third Cut the darkest, roughest, thickest stems right down to the soil. Leave all the strong one-year shoots from the base at full length, since their whole length is next season's fruit.
- Remove swollen buds and clear up Pick off every round, papery bud and destroy it with the prunings. Rake out old leaves from inside the stool and take them away from the fruit area.
- Feed and mulch Apply the nitrogen-rich feed over the whole root spread as the buds start to move, then lay 3 inches (8 cm) of manure or compost over it, kept an inch clear of the stems.
- Plant and propagate Set new bushes 2 inches (5 cm) below their old soil mark and cut them to two buds. Take hardwood cuttings a foot (30 cm) long from clean one-year wood and line them out in a spare corner.
Spring: flowers, frost and the first watch
Blackcurrants break bud and flower early, which is their main weakness in a garden. The strigs of small dull flowers hang under the new leaves and a frost while they are open browns the center of each flower and kills the crop for that year, without harming the bush. If a frost is forecast while the bushes are in flower, throw row cover or an old sheet over them in the evening and take it off in the morning; on a cold still night that is often enough.
The flowers need insects. A cold windy flowering period gives poor set and strigs with big gaps in them, which is not a fault of the bush. Shelter helps more than anything else you can do about it.
Once flowering finishes, keep the ground clean around the stools by hand-pulling rather than hoeing, since the feeding roots run right through the surface layer. Start checking the shoot tips for the white bloom of mildew and the young leaves for the red blisters of aphid.
Note the date the buds burst and the date the first flowers opened. Two or three years of those dates tell you when you actually need the row cover to hand, which is a far better guide than any general advice about your region.
Early summer to picking
From fruit set onwards the bush needs steady water. In a dry spell give each established bush 2 to 3 gallons (10 to 15 liters) a week, applied slowly. Dryness now means small berries and gaps along the strig, and it also shortens the new basal shoots that are extending at the same time, so a dry early summer costs you twice.
Net before the first berry starts to color. Birds will strip a bush in a couple of days once the fruit turns, and netting after you notice damage is netting too late. Keep the net clear of the outer branches and check daily that nothing is trapped inside.
Search the middle of the bushes for sawfly larvae from late spring on, working from the inside out, and pick them off. Cut out any shoot tips carrying mildew. Ease off heavy watering as the berries reach full color, because a sudden soaking after a dry spell splits the skins.
Pick whole strigs, in two or three passes over a week to ten days, taking the outer strigs first and coming back for the shaded ones inside.
| Stage | Check for | Action |
|---|---|---|
| Fruit set | Dry soil under the mulch | Water weekly, 2 to 3 gal (10 to 15 l) per bush |
| Fruit sizing | Sawfly larvae in the center of the bush | Hand-pick; check again every few days |
| First color | Birds | Net now, clear of the outer stems |
| Coloring up | Split skins after rain | Water evenly; pick split fruit at once |
| Full color plus about a week | Tip berry sweet | Pick the whole strig |
After harvest and into autumn
Picking is not the end of the year, and treating it as one is the commonest reason a good bush crops badly the following summer. The new basal shoots are still extending after the fruit comes off, and they are the entire crop for next year. Keep watering in dry weather, top up the mulch if it has thinned, and take the net off so birds can work through the bushes for pests.
Do not feed with nitrogen now. Late soft growth does not ripen before the cold and it is the growth that mildew and frost damage first. Let the bushes slow down naturally as the light goes.
As the leaves fall, rake them out of the stools and away from the fruit area, especially if leaf spot has been about. Once the bushes are bare, walk the row and count the swollen buds bush by bush before you start pruning, so you know which stems to bias the renewal cut towards.
Then the loop starts again: prune out the oldest third, feed, mulch, and grow the wood that will carry next summer's fruit.
Close out the year in your records with three numbers per bush: weight picked, number of stems removed at the winter prune, and number of swollen buds counted. Those three, tracked over three seasons, tell you whether each stool is renewing, starving or infected, long before the crop makes it obvious.