- Japanese grapes: origin and properties
- Planting Japanese Grapeberries
- The most important care measures
- Is the Japanese grape berry hardy?
- Propagating Japanese Grapeberries
- Harvesting Japanese grapes: when and how to do it
- Flavour, Ingredients and Uses of Japanese Grapeberries
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The Japanese grape berry is closely related to raspberries and blackberries. We present the Asian treasure and give tips on cultivation, care and use.
Despite its Far Eastern origin, the exotic Japanese grape can also be cultivated here and produces tasty fruits. In this article you will learn everything about the choice of variety, cultivation, care and harvest time of the Japanese grape.
Japanese grapes: origin and properties
The Japanese grape (Rubus phoenicolasius) belongs to the rose family (Rosaceae) and belongs to the genus Rubus. The species name phoenicolasius consists of the parts phoenix (=crimson, fox red) and lasios (=dense hairy, shaggy) together and alludes to the hairiness of the shoots. The Japanese grapeberry is closely related to blackberry (Rubus fruticosus) and raspberry (Rubus idaeus). Some sources name the Japanese grapeberry as a hybrid between blackberry and raspberry, comparable to loganberry or tayberry. However, this crossing should have taken place naturally, i.e. without human intervention. As the name suggests, the Japanese grape is found in Japan, but is also native to Korea and China. It has been used by people since the end of the 19th century and has also been cultivated in this country since the second half of the 20th century. The Japanese grapeberry is also known as grape blackberry, Japanese raspberry or redbristly raspberry.
It grows as a rampant, 2-3 meter tall and just as wide, upright and deciduous shrub with overhanging or prostrate side shoots. There are only a few thin spines on the red-brown rods. Instead, the shoots are dense and bristly covered with red glandular hairs, which gives the plant an exotic but also extremely elegant appearance. The dark green, three- to five-fold leaves are about 10 centimeters long and are flocked with white underneath. Like its relatives, the Japanese grape berry forms root suckers and can therefore spread well. Old plants can occupy a space of 16-20 m². thesoft pink flowers of the Japanese grape are in small clusters. The flowering period extends from June to July. The flower buds, like the shoots, are red in color and have sticky, bristly hairs. The initially apricot-colored, hemispherical cluster drupes ripen from July to August, then turn deep wine-red and feel slightly sticky.
Planting Japanese Grapeberries
For domestic cultivation, there is no subdivision of the Japanese grape berry into varieties, it has probably not been cultivated until now as it is a rare exotic berry. Sometimes offered as a hybrid berry or among blackberry cultivars, the Japanese grapeberry is strictly a species of its own. Japanese grapeberries are not fussy about their location, as long as it is somewhat sheltered and warm. Similar to blackberries, they grow on any type of soil as long as there is no waterlogging. The ideal location for Japanese grapes is sunny to semi-shady on moderately nutrient-rich soil with a calcareous to neutral pH that stores moisture well. Either you let the vigorous bushes grow wild or you direct the Japanese grape berries to climbing aids or trellis along walls and fences. It can also be grown as a fruit-bearing hedge.
The Japanese grape berries are planted in the spring after the ice saints, as the young plants are still somewhat sensitive to frost in the first few years and the plants that have hardly taken root can be damaged. In this way, it can form strong roots by the first winter and already establish itself somewhat. Before planting, the soil should be enriched with organic material, such as mature compost, and dug up over a large area. Individual Japanese grapes should be placed 150 cm apart so that they can develop well. When planting, dig a deep hole and place the Japanese Grapeberry in it so that it sits about 10 cm lower than before. The shoot buds on the root neck are covered by soil and can develop well.
When planting grapes in pots, the planter should hold at least 10-15 liters and the shrub should be moved to a larger bucket every year. For planting in pots, we recommend a nutrient-rich potting soil, such as our Plantura organic universal soil. It offers young plants aBasic supply with all essential nutrients and promotes root growth and soil life through the high compost content.
Tip: To prevent the Japanese grape berry from spreading excessively in the garden, you should plant a root barrier about 40 cm deep when planting. The shallow roots thus spread only within the barrier by means of root stolons.
Summary: Planting Japanese Grapeberries
- Location: Sunny to partially shaded
- Soil: Moisture retaining, moderately nutritious, calcareous to neutral pH
- Planting time: After the ice saints
- Planting distance: 150 cm
The most important care measures
The Japanese grape berry is extremely easy to care for, because as soon as it has established itself in the garden, you only have to pay attention to a few points. Shrubs that are still young and freshly planted should be watered in dry summers, otherwise fruit formation will stop and branches may die.
In the spring, the nutrients that have been withdrawn over the year should be refreshed with mature compost or a long-term fertilizer such as our Plantura organic universal fertilizer. For this purpose, the fertilizer granules are worked into the surface around the berry bush and decomposes over months, which means that the nutrients contained are only available to the plants slowly and without the risk of being washed out. Another care measure is the pruning of the Japanese grape. The Japanese wineberry bears on the previous year's shoot. Worn canes die after harvest. Therefore, old, harvested and dry shoots are removed close to the ground every year in autumn.
Is the Japanese grape berry hardy?
As an adult plant, the Japanese grape berry is fully hardy. Young plants outdoors should be protected from severe sub-zero temperatures with brushwood or fleece in the first two years. Plants in pots should not be left outside unprotected in winter, because there is a risk that the root ball will freeze through and the plant will be seriously damaged. Japanese grapes should therefore be overwintered in pots in a frost-free place at around 5 °C and in a bright spot in a shed or garden shed.
Propagating Japanese Grapeberries
Japanese grapes can be propagated vegetatively via root suckers or cuttings, but also generatively via their seeds. However, growing seedlings from Japanese grapevine seeds is not an easy task. First, the pulp around the seeds has to get wet and colddetach. The seeds are cold germs, so they need a long-term cold stimulus in order to be able to germinate at all. After the cold treatment, which lasts 4-6 weeks, the seeds are spread superficially on the cultivation substrate and only lightly pressed. This is necessary because they are also light germinators that need light to trigger germination. At about 15-18 °C and high humidity, germination takes about 2-4 weeks. After another four weeks, the tender young plants can be transplanted for the first time.
The numerous root suckers of the plant are ideal for propagating the Japanese grape berry much faster and easier. They can be cut off the mother plant with a spade in autumn or spring, dug up and placed in a new location. Even cut shoot cuttings that are about 15 cm long usually root quickly in moist soil and quickly form independent plants. Another alternative are the mostly naturally formed sinkers. Roots develop on shoots lying on the ground when they come into contact with the earth. If the sinkers are already well rooted, you can use pruning shears to cut the connection between the rod and the mother plant, dig up the sinker and move it.
Harvesting Japanese grapes: when and how to do it
The deep red, slightly sticky fruits of the Japanese grape are harvested between July and the beginning of September. When fully ripe, the cluster drupes, like raspberries, detach well and easily from the stalk and can be collected.
Tip: Incidentally, maggots and many other pests avoid the Japanese grapeberry, so you can harvest and enjoy the fruits without hesitation. It is believed that the sticky bristle hairs on shoots and calyxes keep away many of the typical raspberry pests, such as the raspberry beetle (Byturus tomentosus).
Flavour, Ingredients and Uses of Japanese Grapeberries
The taste of ripe Japanese grapes is sweet, aromatic and pleasantly refreshingly tart and vinous. It is ideal for snacking straight from the bush. However, the fruits cannot be stored and must therefore be processed immediately after harvest.
True delicacies are chocolate-dipped raisins, homemade Japanese raisin jam or marmalade, and fruit wine too. In principle, all types of preparation of raspberries or blackberries, such as juice, chutney or liqueur, are also possibleConvertible into recipes for Japanese grapes. Due to its high mineral content, the Japanese grape berry is very he althy and scores particularly well with its high vitamin A and C content.
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