The currant plant belongs to the category of berries. The cultivation of these berries has seen exponential growth in recent years. Currants, of which there are several species and varieties that we will explore today, are extremely hardy plants that adapt well to different climates. The ideal conditions for their cultivation are hilly or mountainous areas. The plant belongs to the botanical family Grossulariaceae, with approximately 150 species.
Let’s now examine the botanical characteristics of this plant, how it is cultivated, and what care it requires.
The currant plant is a perennial shrub, usually with a bushy growth habit, which, depending on the variety and cultivation technique, can reach heights between 1 and 3 meters. It is a deciduous plant, meaning it sheds its leaves in the autumn. It has a shallow root system, mainly concentrated in the top 30 cm of soil.
Currant leaves are simple and palmate with 3-5 lobes. The upper surface is smooth, while the lower surface is pubescent. The leaves have well-developed petioles and lack stipules. The flowers, generally self-fertile (except in Ribes nigrum), consist of 5 sepals that are greenish or reddish-brown, sometimes spotted with red. The sepals are as wide as the petals but twice as long.
The fruit is a translucent berry with a round shape, grouped in clusters. The color varies depending on the cultivated species (red, white, black). The diameter of the currant berry is usually less than a centimeter. The pulp has a sweet-tart taste in red and white currants, while it’s more bitter in black currants. Numerous small seeds are found inside the berry.
The currant plant starts producing fruit from the second year of planting, but full production begins around the 4th to 5th year. From this point, currant plants remain productive for 10-12 years, ensuring excellent yields.
Choosing the Variety
The most suitable types of currant plant for cultivation, both in domestic and professional settings, are:
- Red Currant (*Ribes rubrum*)
- Black Currant (*Ribes nigrum*)
- White Currant (*Ribes sativum*)
Let’s explore the main varieties within these three types. It’s important to note that most species are of foreign origin but adapt well to our territory.
- Gigante di Booskoop: A vigorously growing plant with small clusters of 8-10 berries. It has a tart and highly aromatic flavor.
- Noir de Bourgogne: A French variety that is vigorous and hardy, with shorter clusters. It’s highly productive. You can find it here.
- Junifer: A French variety that is vigorous and highly productive, but susceptible to late frosts. It has early maturity and medium-length clusters.
- Rovada: A Dutch late-maturing variety. It’s highly productive and vigorous, with long and easily harvestable clusters. The berries are large, juicy, and aromatic. This variety is suitable for direct consumption and large-scale production.
- Red Lake: An American variety, very productive and moderately vigorous, ideal for direct consumption.
- Jonkheer Van Tets: An old variety with excellent productivity. In this variety, fruit maturity is early, and the currants are particularly large and juicy (available here).
- Zitavia: An early-maturing variety, vigorous, and moderately productive. Its clear, firm fruits are pleasant.
- Blanka: A late-maturing, highly vigorous variety. It has high productivity, with clusters of 18-20 berries.
Climate Requirements of the Currant Plant
The currant plant is generally very hardy and resistant to winter cold (especially red currants). However, it is sensitive to late frosts (especially during the flowering phase) and excessive heat in the summer months. For this reason, currant cultivation is usually practiced in hilly and mountainous areas, even at high altitudes, with moderate sun exposure.
Soil and Fertilization
The currant plant is not very demanding in terms of soil. It adapts well even to poorer soils, where it produces more aromatic and fragrant fruits, though with lower yields. The ideal soil is soft and well-draining, slightly acidic, with a pH between 6.2 and 6.7. Before planting, it’s advisable to apply a base fertilization with well-matured animal manure, which should be incorporated during soil preparation.
Training and Planting Spacing
For productive currant cultivation, the most commonly used forms are the bush and the cordon (espalier). The bush form is free-growing and doesn’t require support. It’s planted with a spacing of 2.5 meters between rows and 1.5 meters between plants within a row.
The cordon form, on the other hand, is often used in larger-scale production. It allows for early fruiting and consistent sun exposure, leading to improved fruit quality. This training form also facilitates pruning operations, harvesting, and interrow cleaning. The planting density in this case is one meter between plants and two meters between rows. A support structure made of wooden posts is required for this planting type, with posts set at a height of 1.80 meters above the ground and spaced 5 meters apart. Two steel wires are stretched on this structure, one at a height of 40 cm and the other at 1.5 meters above the ground. This setup aids in tying the branches that form the plant’s framework. In home cultivation, you can also opt for the tree form.
The best period for planting currants extends from early autumn throughout winter. These plants tolerate low temperatures well. We have already covered techniques for planting fruit trees. Typically, young plants are purchased from nurseries. Alternatively, propagation can be done through hardwood cuttings, taken from parent plants that have been earthed up in autumn and then removed in spring.
The currant plant is very hardy and doesn’t require irrigation, not even in the summer months. However, during extremely hot and dry summers, especially in the early years of cultivation, emergency irrigation can be beneficial. To improve soil moisture retention and reduce frequent weeding, it’s a good practice to apply natural mulch around the base of the plant in spring.
Pruning operations on the currant plant are quite simple. However, they need to be performed regularly to ensure abundant yields. This operation is carried out in the cordon training system. During planting, pruning is based on the number of branches present on the new plant. Generally, three well-positioned branches are chosen to form the final framework. Any excess branches are removed. If conditions don’t allow for three branches, one or two can be chosen.
During the first summer, green pruning is performed to remove excess shoots. The branches intended for future production are pinched back to allow lateral bud development. These side shoots will produce the “brindles” (one-year-old shoots that develop on two- or more-year-old branches) that bear fruit in the following year.
In the years following the first, production pruning is done. This involves summer pruning in June, where all new lateral shoots are pruned to the length of five leaves. During this pruning, shoots at the base of the plant are cut off. In the winter pruning for production, old, damaged, or poorly positioned lateral branches are removed. Additionally, the “dards” (the older, non-fruiting shoots) are removed to maintain currant production on the brindles, which offer higher and better-quality fruit yields.
Harvest and Uses
Harvesting currants, depending on the variety, typically occurs from late June to September, especially for red and black currants. The harvesting technique is fairly quick, as clusters are easily disarticulated at the base of the peduncle. The ripening of currants spans up to 3 weeks, so harvesting occurs in multiple stages.
The fruits of red and white currants are enjoyable for fresh consumption. However, they are often used for making jams, jellies, and syrups as well. Black currants are less suitable for fresh consumption but are in high demand in the confectionery industry.
Biological Pest Defense
The currant plant is hardy and resistant to adversity and pests. Among fungal diseases, the most concerning is powdery mildew, while among pests, aphids and scale insects can pose problems. For strategies on combating these issues, refer to specific resources.
- Journal of Food Science – Chemical Composition of Currant Seed Extracts and Their Protective Effect on Human Lymphocytes DNA: This research focused on the chemical composition of seed extracts from black, red, and white currants. The study identified 35 compounds from these extracts. Black currants, in particular, contained protocatechuic acid and p-hydroxybenzoic acid, among other compounds. The extracts were tested for their protective effect on human lymphocytes DNA. The results showed that black currant seed extracts, especially from the cultivar Malling Jewel, had a significant antioxidant potential. The study concluded that currant seed extracts could have beneficial effects in various diseases, primarily due to their antioxidant properties.
- Food & Function – Chemopreventive properties of raisins originating from Greece in colon cancer cells: This study investigated the effects of Corinthian raisins (Currants, CR) and Sultanas (S) on human colon cancer cells. Both CR and S extracts showed anti-radical activity in vitro. The research found that these extracts suppressed cell proliferation and reduced inflammation markers. The beneficial properties of these dried grapes are attributed to their high content of phenolic compounds.