Genus Zhoster(Rhamnus) family zhosterovye (Rhamnaceae) includes about 100 species that are widespread in nature and live on all continents, with the exception of Australia. They choose thickets of bushes for settlement, not swampy river banks or undergrowth of light deciduous forests. The greatest variety of species is in Asia.
The main decorative advantage of josters is large, beautiful leaves with clear veins. Their flowers are small, unimportant, unisexual and most often located on the same plant, although there are dioecious species. An additional decoration is black pea-sized drupes that ripen in different species in summer or autumn.
Earlier, the alder-shaped beetle was reckoned to this genus, now attributed to the genus Krushin (Frangula) called alder buckthorn (Frangula alnus).
Joster laxative, or buckthorn laxative(Rhamnus cathartica). The natural range stretches from Western Europe to Siberia and Central Asia, it is confined mainly to the forest-steppe and steppe zones. In Central Russia, the species tends to the more southern regions and often grows on chernozem soils containing lime. It avoids humid places, inhabits xerophilous woodlands, hillsides and forest edges.
Strongly branching shrub up to 3 m high, or a low tree up to 7 m high. The bark is exfoliating, with thorns on the branches. Covering buds. The leaves are arranged more or less oppositely, oval, with arcuate venation, clearly visible 3 pairs of veins. Flowers are small, greenish, dioecious, collected in bunches of 10-15 pieces. In male flowers - 4 stamens, in female - 1 pistil with a three-part column. Juicy drupes, when ripe, immediately turn black (do not turn red, like a laxative buckthorn), sometimes have a bluish bloom. Joster laxative blooms in May, the fruits ripen in September. The first fruiting occurs at the age of 6.
Joster laxative is decorative and suitable for landscaping. In nature, it settles with the participation of birds that feed on its fruits and seeds. Rh. cathartica, introduced at the end of the 19th century from Europe to North America, after 100 years naturalized there, and in Canada ranked among dangerous weeds.
Zhoster Imeretian (Rhamnus imeretina). The natural area of the Imeretian joster is the mountain forests of the Transcaucasus. The species is listed in the Red Book of the USSR and is protected in reserves.
Shrub about 1.5 m high. Planting in Moscow throughout the growing season retains a high degree of decorativeness. Especially elegant are glossy, oblong-ovoid leaves, on which veins are clearly visible. The leaves are large, up to 25 cm long, more than 10 cm wide. In autumn, the leaves turn bronze-purple. The flowers are small, yellow-green, as nondescript as those of the laxative joster. The fruits are black drupes. Flowering occurs at the age of 7-9 years, usually in May-June, the fruits ripen in September.
Zhoster Ussuri(Rhamnus ussuriensis)... The natural range is in the Far East and East Asia, where the species lives in deciduous forests, on fertile soils.
In Moscow, the shrub reaches a height of 4 m. Oblong-elliptical leaves, glossy and bright green, light gray below. They are dense to the touch, dotted with a network of deep veins. In the axils of the leaves, yellow-green flowers are collected, which are melliferous. The bush blooms at 4 years of age, in May-June, bears fruit well. The fruits are black drupes. The species is winter-hardy and decorative.
Zhoster daurskiy (Rhamnusdavurica)... The natural range of the species is in Eastern Siberia, the Far East and East Asia. It lives in coniferous-deciduous forests, river floodplains.
Externally, the shrub is very similar to the Ussuri zhoster. It has broadly elliptical leaves, 3-5 cm wide, with 4 pairs of veins. In Moscow, a shrub up to 5 m in height. It blooms at the age of 5, bears fruit well. Winter-hardy and decorative.
Alpine joster(Rhamnus alpine). The natural range of the species is in Southern Europe and North Africa. In Moscow, the shrub will grow about 1.2 m high. The leaves are dense, elliptical, 4-7 cm long, with 8-12 pairs of veins. Blooms at the age of 10. The fruits, not having time to ripen, crumble.
Diamond joster(Rhamnus diamantiaca) - grows in the basins of the Amur and Ussuri rivers, as well as in Northeast China and North Korea. Thorny shrub, in Moscow about 5 m tall, bears fruit from the age of 10. Leaves broadly elliptical or oval-rhombic, up to 6-7 cm long, often bluish or grayish above, light green below. Blooms from early June. Drupes are black, ripen in the third decade of September.
Narrow-leaved joster (Rhamnus leptophylla) Is a dioecious species from China, where it grows in the undergrowth of mountain forests. Leaves from obovate to elliptical and oblong, medium-sized, up to 5 cm long. Drupes are black, spherical, 4-6 mm in diameter. It freezes in Moscow, but quickly grows to a height of 1.2 m. It does not bloom.
Small-leaved joster(Rhamnusparvifolia) - a plant of sunny hills and rocky slopes of Eastern Siberia, Mongolia, China. In nature - 1.2 in height, in Moscow twice as high. The leaves are almost rhombic, medium-sized, up to 3 cm long, small-town on the edge, dull green. Fruits are spherical or obovate black little fleshy drupes. Fruiting from the age of 11, at the end of September. Compared to other species, less leafy, but still decorative. Fully winter-hardy.
Zhoster useful(Rhamnusutilis)... Natural range - in the east of China. It grows among shrubs on the slopes of mountains and hills. In Moscow - a shrub up to 2 m high, with oblong-elliptical leaves 6-14 cm long, when dried they turn yellow. The fruits are juicy, black. It is close to the Daurian zhoster, but inferior to it in decorativeness and winter hardiness.
For planting zhosters, an area protected from cold winds is required, maybe a little shaded. They like well-drained but moderately moist soil. Since zhosters are unpretentious, they can withstand rather poor soils, they can grow on sandy loams and light loams, and develop worse in peat areas. For them, soils with a neutral or slightly alkaline reaction of the soil solution are favorable. When planting, dolomite flour or lime is added to the planting pit.
Zhosters are decorative and are used in landscaping, especially appreciated for the construction of impassable thorny hedges. Plants are planted in hedges at a distance of 40-50 cm, formed with a height of 1-1.5 m, subjecting to shearing in early spring and as they grow back in summer. A dense closed hedge can be obtained in 4-5 years.
Joster is propagated by seeds and vegetatively. Seeds are sown in autumn so that in winter they undergo natural stratification under the snow.
Joster can be propagated by root suckers, dividing the bush and layering. It reproduces poorly by summer cuttings; even with growth stimulants, it has a low rooting rate. 15% of summer cuttings are rooted in the alpine zhoster, up to 50% in the daurian and laxative zhoster, and up to 70% in the useful and Ussuri zhoster.
Diseases and pests
Observations of the planting of a laxative ghoster in Moscow showed that rust foci appear on the plants every year. The disease affects leaves, less often fruits and young stems, after which the plants develop weaker. In addition, aphids, leafworms, euonymus ermine moth colonies, as well as buckthorn and buckthorn larvae feed on the leaves.
The leaves of the Imeretian joster were very rarely damaged by aphids and buckthorn larvae.
Zhosters are honey plants that attract bees and other insects.
Zhosters laxative and Imeretian have medicinal properties. Joster laxative is officially recognized and included in the list of pharmacopoeial plant species. In the folk medicine of Transcaucasia, the fruits of the Imeretian joster are used as a laxative.They are distinguished by a pungent odor and a bitter taste. Contains anthraglycosides, flavonoids, sugars, pectin and gum.
The bark, leaves and fruits of the Ussuriisky and Imeritinsky zhoster are suitable for obtaining natural dyes - green, blue, lemon, brown and purple.
Josters have a heavy and very strong wood that retains its color, so it is used in handicrafts after turning or joinery, for the manufacture of plywood and furniture parts.
Photo by the author