Gadenin日本語Get the appPlant in the dormant season if you can
Bare-root bushes go in any time the plant is leafless and the ground is neither frozen nor waterlogged. Early in the dormant season beats late: blackcurrant roots keep working whenever the soil is above roughly 45F (7C), so a bush planted early is already anchored and drawing water by the time the buds move. A bush planted right at the end of dormancy pushes leaves before it has roots to supply them, and spends its whole first summer catching up.
Container-grown bushes can go in at almost any time, but they establish best dormant and they still need watering right through their first summer. If you must plant one in full leaf, keep the rootball intact, water it in hard, and check it twice a week until the leaves drop.
Bare-root plants will not forgive dry roots. If the bed is not ready the day they arrive, heel them into spare soil or a bucket of damp compost and get them planted within a week.
What the site has to give them
Blackcurrants are the least fussy of the soft fruits about light and the fussiest about feeding. They will crop in a spot that gets sun for only part of the day, which is why they end up in the awkward corner of most gardens, but they will not crop on thin, hungry, dry soil no matter how much sun it gets. Deep, moisture-holding ground with plenty of organic matter is worth more to them than an extra two hours of afternoon sun.
Avoid frost pockets. The flowers open early, they are borne in hanging strings called strigs, and a frost while they are open destroys the crop for that year without damaging the bush at all. A slope where cold air drains away, or shelter on the side the cold comes from, is the difference between a full crop and a handful of berries in a bad spring.
| Site factor | What blackcurrants want | What goes wrong otherwise |
|---|---|---|
| Light | Full sun to light shade, four hours or more | Deep shade gives soft growth, mildew and few strigs |
| Soil | Deep, heavy, rich in organic matter | Thin sandy ground gives small berries that drop early |
| Soil pH | 6.0 to 6.5 | Above 7.0 the leaves yellow between the veins |
| Moisture | Never dries out, never stands wet | Drought at fruiting drops half the crop off the strig |
| Frost | Out of hollows where cold air pools | Open flowers browned overnight; no fruit that season |
| Wind | Sheltered enough for insects to fly | Cold windy sites get poor pollination and blank strigs |
Deep planting is the whole trick
Almost every other fruit bush is planted at the depth it grew. Blackcurrants are not. Set the bush so that the old nursery soil mark on the stem ends up about 2 inches (5 cm) below the finished surface, so the base of the stem and the lowest buds are buried.
The reason is the way blackcurrants crop. Fruit comes on wood made the previous summer, and the best of that wood comes from strong new shoots that break from below ground, not from side shoots high up on old stems. Buried buds break out as new basal shoots and turn the plant into a stool of eight or ten stems within three years. Planted at the same depth as it came out of the pot, a bush stays a single-legged plant with all its buds in the air, and you spend the next decade wondering why it never renews itself.
The other benefit is buried insurance. A stool with shoots coming from below ground can be cut to the ground and rebuilt, which is exactly what you do if you ever have to renovate an old bush.
- Clear the ground first Take out every scrap of perennial weed root from an area about 3 feet (90 cm) across. A blackcurrant stool is a thicket of stems at ground level and you will never weed inside one properly once it is established.
- Dig wide, not deep Open a hole about twice the width of the rootball and only a little deeper. Fork the base so the roots can get down, and mix a bucket of well-rotted manure or compost into the soil you took out.
- Find the old soil mark On a bare-root bush the stem changes color where it left the nursery soil. On a container plant, use the surface of the compost. That line is your reference point, not the top of the roots.
- Set it 2 inches (5 cm) low Backfill so the soil mark disappears 2 inches (5 cm) below the finished level. Lay a cane across the hole to sight the level if you are not sure. Firm with the ball of your foot, not by stamping.
- Water in and mulch Water thoroughly enough to wash soil into every gap between the roots, then mulch 3 inches (8 cm) deep with compost or well-rotted manure over the whole root area, keeping it just clear of the stems.
- Cut every stem to 2 inches (5 cm) Prune the whole bush down to two buds above the soil. It feels brutal and it costs you the first year's fruit, but it forces the strong basal shoots that the bush is built from. A newly planted bush left uncut makes a weak crop and stays a poor shape for years.
If the bush arrives already cut hard by the nursery, check the stems: if none is longer than about 4 inches (10 cm), it has been done for you and you can leave it alone.
Spacing, and what happens when you crowd them
A mature stool is a wide, arching thing, considerably bigger than the stick you plant. Give each bush 5 feet (1.5 m) in the row and 6 feet (1.8 m) between rows. That is roughly a third more room than most gardens allow them, and the reason so many blackcurrants get mildew in the middle and never ripen the fruit on the inside of the bush.
Air moving through a stool is what keeps mildew off the shoot tips and dries the fruit after rain. It is also what lets you get a hand in to cut out old wood in winter without lying on the ground. If you are short of space, grow fewer bushes and prune them properly rather than squeezing more in.
| Layout | Spacing in the row | Between rows | Notes |
|---|---|---|---|
| Open ground row | 5 ft (1.5 m) | 6 ft (1.8 m) | The standard; allows a barrow and a person between rows |
| Single bush in a border | 5 ft (1.5 m) all round | Not applicable | Keep other plants back from the stool base so you can prune |
| Tight garden row | 4 ft (1.2 m) | 5 ft (1.5 m) | Workable, but expect more mildew and stricter pruning |
| Large container | One bush per 18 in (45 cm) pot | Not applicable | Needs daily water in summer and a top-dress of compost each spring |
Write down what you planted and where
Blackcurrant stools all look alike after three years, and a stool is pruned on the age of its stems, so the one thing you need to know is how old each part of the plant is. Record the planting date and sketch the position of every bush in the row, numbering them from one end. From then on, note against each bush how many stems you removed each winter, and you will always know whether a stool is being renewed or slowly ageing.
Also note the date the first flowers opened and whether any frost caught them. Two or three years of those dates tell you whether your site genuinely needs frost protection at flowering, or whether the one bad year was just a bad year.
The most useful single record is a photo of each bush taken in the dormant season, before you prune. Side by side over three winters, the photos show whether new basal shoots are actually coming, which is the health check that matters most.