Last Updated on October 13, 2022 by Real Men Sow
Blackcurrants can be grown easily and produce a lot of dark purple berries mid-summer. They are rich in vitamin C and can be used in pies, jams, and cordials. You can also grow blackcurrants in containers if you have limited space.
Blackcurrants can be purchased as two-year-old plants. They are sold either bare-root (with no soil around the roots), or in containers. To avoid viruses, make sure you only buy certified FPCS plants.
There are many great varieties available. Look for ones with an RHS Award of Garden Merit (AGM). This means they have been tested well and should be able to grow reliably. You can grow multiple plants if you have the space. Choose varieties that produce in the early or late seasons to ensure harvests throughout the summer.
Although blackcurrants are tolerant of most soil types, they prefer soil that is well-drained and moisture-retentive. They are best suited for full sun but can tolerate some shade. Avoid areas that are susceptible to frosts or cold winds, as these can cause damage and decrease crop yields. Modern cultivars are more resistant to cold.
Planting is best done during the dormant period, which runs from late October through March. However, it is best to avoid planting in winter if the soil has been very wet or frozen. You can plant containerized plants all year. They are available at nurseries, garden centers, and online. You can plant spring or summer plants, but they need to be kept hydrated during dry heat.
How to plant Blackcurrants
Clear the area of perennial and invasive weeds before you plant. This is especially important for light soil. A balanced fertilizer can be added. Make sure to dig a hole twice the size of the root ball and then spread the roots. Both container-grown and bare-root bush plants should be planted 5 cm (2in) deeper than before.
This will encourage strong shoot growth from the base. Standard-trained plants should be planted at the same soil depth that was used previously. Plant the blackcurrants 1.5m to 1.8m (5-6ft) apart. For vigorous cultivars, the spacing should be wider. Blackcurrants should always be pruned immediately after they are planted
Planting in a container
Because of their growing habits and size, blackcurrants don’t do well in containers for long periods. They can be grown in containers for a couple of years if space is limited, particularly compact cultivars like ‘Ben Sarek and ‘Ben Gairn. Transplant them into the ground if they begin to perform poorly.
A large container should be approximately 45cm (18in.) in diameter and depth. You can use soil-based compost like John Innes No.3, and then add 20-30% of multi-purpose compost, 10% perlite, sharp sand, or horticultural grit. It’s also possible to use peat-free multipurpose compost with 20% perlite, sharp sand, or horticultural grit.
General Care for Blackcurrants
Feeding and watering
Blackcurrants only require watering during dry spells. It is best to water at ground level, rather than above. To prevent skin splitting, avoid excessive watering during ripening.
Use high potassium general fertilizer in late winter, which is in February. Sprinkle two tablespoons of the fertilizer per square meter/yard all around the base. You can also use blood, fish, and bone meal. Additional high-nitrogen feeds can be beneficial for weak plants, such as ammonium sulfate at 25g (3/4 oz) per square yard.
Weeding and mulching
To suppress weeds, and reduce water loss, apply a mulch layer of 5cm (2in), such as mushroom compost or well-rotted manure around plants after they have been fed in February. Leave a space around the base of your stem to prevent rotting. To avoid damaging new shoots at the base, you should not hoe close to stems.
Blackcurrant Plants in containers
Container plants require regular watering throughout their growing season as they dry quickly. Use liquid feed in the summer months or mix in slow-release fertilizer. Spring is the best time to top-dress. Begin by gently removing the top 5cm (2in.) of compost. This will prevent any root or shoot disturbance. Mix fresh potting compost with a granular fertilizer to replace it.
Container-grown blackcurrants should be re-potted every two to three years in the winter. You can trim a few roots from the root ball, and then you can remove some of the old compost. 3. Place the pot back in the same container, or use a slightly larger container.
Protecting Blackcurrant flowers from frost
Protect flowers in bloom by covering them with fleece and cloth on nights when frost is predicted.
Blackcurrants can also be propagated using hardwood cuttings from virus-free plants that have been planted in the mid-autumn through winter. The length of the cuttings should not exceed 20cm (8in).
Blackcurrants grow best when they have strong young growth from the previous year. This is why they are often grown as multi-stemmed shrubs with stems growing from the base. They should be pruned in winter to encourage new stems.
If space is tight, standard-trained blackcurrants can be useful. Half-standards or standards look like lollipops with a single straight stem measuring 60-100cm (2-3/4 ft) high and a bushy top.
To encourage strong growth, reduce the height of all shoots from autumn to spring to 2.5 cm (1in) above the soil. This may seem extreme, and your first year’s fruit might be lost. However, it will benefit you in the long term. Half of the shoots can be retained on well-developed plants. This will yield a small crop.
If container-grown plants are still active, do not prune them too hard when you plant them. After planting, standard-trained plants don’t need to be pruned.
Young Blackcurrants Bushes
If the growth is strong for three years, you can prune lightly in winter or autumn. You should only remove any weaker or lower-lying shoots. If growth is slow, you can prune the plants hard and cut at least half of the shoots to near ground level.
Established Blackcurrant Bushes
You can do some pruning at pick time. For easy picking, prune out large branches that are full of fruit. However, you should wait until winter to do the main pruning. Each year, remove 25% to 30% of the branches. This is to get rid of old, unproductive wood, weak growth, and low-lying branches. To encourage strong growth, cut the branches as low as possible. Also, remove any weak shoots.
Reviving Old Neglected Bushes
Old bushes that are healthy can be rejuvenated by cutting the weakest and youngest branches to 2.5 cm (1in) below the ground in winter. To thin the new growth, you will need to trim 12 young shoots.
Trained As Standards
To encourage new shoots, trim back approximately 25% of your plants that are already established. In order to keep the lollipop, remove any sprouts from lower down on the main stem.
Blackcurrants can ripen in the early summer, depending on their variety. Modern varieties such as the Ben Sarek, Ben Hope, and Ben Connan are easiest to harvest.
Older varieties ripen more unevenly. The top truss of currants should be ready first. Pick ripe currants separately in this instance. Consume within a few days after harvesting. Blackcurrants can also be frozen, cooked, or made into jam, jelly, or smoothies.