Sea-buckthorn (Hippophae rhamnoides), also known as sea buckthorn, sandthorn, sallowthorn or seaberry, is a species of flowering plant in the family Elaeagnaceae, native to cold-temperate regions of Eurasia. It is a spiny deciduous shrub. The fruit has culinary uses, while its extracts, including its oil, are used in the cosmetics industry and within traditional medicine. It is also used as animal fodder, in horticulture, and for ecological purposes.
Description and biology
Sea-buckthorn is a hardy, deciduous suckering shrub that can grow between high, rarely , forming extensive clonal colonies by root sprouts. It has rough, brown or black bark and a thick crown of greyish-green foliage. Like many species of the family Elaeagnaceae, the young shoots and leaves are covered in small silvery scales. The leaves are alternate, narrow and lanceolate, 1–8 cm long and up to 1 cm broad with silvery-green surfaces at first; the upper side darkens to mid to dark grey-green through the summer as the scales wear off, while the underside remains silvery. It is dioecious, with male and female flowers growing on different shrubs. The sex of seedlings can only be determined at the first flowering, which mostly occurs after three years. The male inflorescence is built up of four to six apetalous flowers, while the female inflorescence normally consists of only one apetalous flower and contains one ovary and one ovule. Fertilisation occurs solely via wind pollination, so male plants need to be close to female plants to allow for fertilisation and fruit production.
The globose to oval fruit are 6–8 mm diameter, grow in compact dense clusters, and are typically bright orange, but vary from pale yellow to dark orange. The individual fruit weigh between 270 and 480 mg.
The plants have a developed and extensive root system, and the roots live in symbiosis with nitrogen-fixing Frankia bacteria. The roots also transform insoluble organic and mineral matters from the soil into more soluble states. Index page from publisher is here. Vegetative reproduction of the plants occurs rapidly via root suckers.
Fruit
The fruit contains sugars, sugar alcohols, fruit acids, vitamins, polyphenols, carotenoids, fibre, amino acids, minerals, and plant sterols. Species belonging to genus Hippophae accumulate oil both in the pulp and in seed of the fruit. Oil content in the pulp is 1.5–3.0%, while in seeds, oil is 11% of the fresh weight.
Major sugars in sea-buckthorn fruit are fructose and glucose, with total sugar content of 2.7–5.3 g/100 ml of juice. The typical sourness of the fruit is due to high content of malic acid (0.8–3.2 g/100 ml of juice) while astringency is related to quinic acid (1.2–2.1 g/100 ml of juice). Major sugar alcohol in fruit is (0.15–0.24 g/100 ml of juice).
Phytochemicals The fruit is rich in phytosterols (340–520 mg/kg), being the major sterol compound as it constitutes 57–83% of total sterols.
Flavonols were found to be the predominating class of phenolic compounds, while phenolic acids and flavan-3-ols (catechins) represent minor components.
Taxonomy Hippophae rhamnoides is in the family Elaeagnaceae in the order Rosales.
Subspecies Seven subspecies are accepted, with three in Europe and four more in Asia. The subspecies vary in size, shape, number of main lateral veins in the leaves and quantity and colour of stellate hairs. The central Asian subspecies grow much taller; the European subsp. rhamnoides only reaches 5 m, but the Chinese subspecies are reported to reach 15 m to even 18 m tall.
Hippophae rhamnoides subsp. carpatica Rousi — Carpathian Mountains in central and eastern Europe Hippophae rhamnoides subsp. caucasica Rousi — southeastern Europe (Bulgaria), southwestern Asia in Iran, Turkey and the Caucasus Mountains Hippophae rhamnoides subsp. mongolica Rousi — east-central Asia Hippophae rhamnoides subsp. rhamnoides — northern & western Europe Hippophae rhamnoides subsp. turkestanica Rousi — west-central Asia Hippophae rhamnoides subsp. wolongensis Y.S.Lian, K.Sun & X.L.Chen — central China Hippophae rhamnoides subsp. yunnanensis Rousi — southwestern China, Tibet
An eighth subspecies Hippophae rhamnoides subsp. fluviatilis Soest is accepted by the Euro+Med-Plantbase, but treated by POWO as a synonym of nominate subsp. rhamnoides. This is claimed to have fewer thorns than other subspecies, and is used for breeding, due to easier harvesting methods.
Etymology The genus name Hippophae comes from Ancient Greek ἵππος (híppos), meaning 'horse', and φάος (pháos), meaning 'light', and is due to the ancient Greeks use of sea-buckthorn leaves as horse fodder to make their coats shine more. The specific epithet rhamnoides derives from Rhamnus plus -oides, resembling, referring to the superficial similarity to the buckthorn genus Rhamnus.
Distribution Hippophae rhamnoides is native to cold-temperate regions of Europe and Asia, between 27° and 69°N latitude and 7°W and 122°E longitude. These regions include the North Sea coasts of Great Britain, the Netherlands, and Denmark, the Baltic coasts of Finland, Poland, Latvia, and Germany, the Gulf of Bothnia in Sweden, as well as coastal areas of the United Kingdom, Norway and the Netherlands. In Asia, H. rhamnoides can be found in the northern regions of China, throughout most of the Himalayan region, including India, Nepal and Bhutan, Pakistan and Afghanistan. It is found in a variety of locations: on hills and hillsides, valleys, riverbeds, along coastal regions, on islands, in small isolated or continuous pure stands, but also in mixed stands with other shrub and tree species. H. rhamnoides has also recently been planted in countries such as Canada, the United States, Bolivia, Chile, Japan and South Korea.
The current total area of H. rhamnoides is about 3.0 million ha worldwide. This number includes both wild and cultivated plants. Of these, approximately 2.5 million ha are situated in China (1.0 million ha of wild plants and 1.5 million ha in plantations), 20 000 ha in Mongolia, 12 000 ha in India and 3 000 ha in Pakistan. This makes China the largest agricultural producer of H. rhamnoides. Approximately 10 000 acres of the plant are planted in China each year for berry production as well as eco-environmental improvement. As of 2003, approximately 100 km of field shelterbelts were planted in Canada each year, and over 250 000 mature fruit-producing plants were grown on the Canadian prairies with an estimated annual fruit supply of 750 000 kg. Other countries that grow H. rhamnoides as an agricultural plant include for example Germany and France.
Ecology It is particularly drought- and salt-tolerant and can thus be successfully used for land reclamation, against further soil erosion, as shelterbelt or in agroforestry. These characteristics are mainly due to the deep root system that the plant develops. For example, in eastern China, new agroforestry systems have been developed to reclaim land with high salinity contents and H. rhamnoides is included in the system as shelterbelt, providing a habitat to different birds and small mammals.
Wildlife habitat and conservation Sea-buckthorn provides habitats for various wildlife species. Its dense bushes offer shelter, while its nutrient-rich berries serve as a food source for birds and small mammals. The berries are eaten by thrushes, particularly fieldfares, and warblers like blackcaps and common whitethroats, and also by larger species like magpies. In regions like Ladakh, these shrubs support a range of native wildlife, providing both cover and food for birds and small mammals. In the Canadian prairies, species such as sharp-tailed grouse, grey partridge, and common pheasants rely on sea-buckthorn for food and shelter. Its importance as a wildlife habitat has been documented across multiple regions, highlighting its role in promoting biodiversity.
Soil Sea-buckthorn may enhance soil physicochemical properties, particularly through its ability to fix nitrogen in specialised root nodules, contributing to increased soil fertility and productivity over time. Nitrogen fixation in sea-buckthorn occurs through a symbiotic relationship with Frankia bacteria, which add an estimated 180 kg of nitrogen per hectare annually to the soil. This process supports soil fertility by increasing nitrogen content, along with added phosphorus and organic matter.
The plant's root system is extensive and efficient, with taproots reaching depths of up to 4 metres, while horizontal roots spread up to 10 metres. It stimulates soil microbial activity through exudates and organic matter from fallen leaves and plant residues, enhancing soil health overall.
Additionally, as sea-buckthorn plantations age, soil fertility improves, evidenced by elevated carbon and nitrogen accumulation This progressive soil enhancement makes sea-buckthorn valuable for land restoration, particularly in degraded temperate regions.
Land reclamation Sea-buckthorn can be used for land reclamation, alongside trees like pine, larch, black locust, alder, sycamore maple, manna ash, silverberry, and wild privet. Its strong root system effectively stabilises slopes, reduces surface runoff, and controls sediment transport, particularly in areas prone to erosion from rainstorms.
Uses Nutrition The fruit has a high vitamin C content, approximately 400 mg per 100 grams. Additionally, the fruit has high concentrations of vitamin E and vitamin K. The berries also contain vitamin B12.
The main carotenoid is the provitamin A, beta-carotene, while other carotenoids include zeaxanthin, and lycopene.
The most prevalent dietary minerals in sea-buckthorn fruit are potassium (300–380 mg/100 g), manganese (0.28–0.32 mg/100 g), and copper (0.1 mg/100 g).
Culinary The berries are usually washed and then pressed, resulting in pomace and juice. The fruit pomace can be used to obtain oil, natural food colour (yellow/orange) or jam, while the juice is further processed and packaged. The leaves of the shrub can be air dried, eventually ground, and used for tea.
Other uses Because of its tolerance against strongly eroded, nutrient-poor and sometimes salty soils, the plant has been used for land reclamation or as shelterbelt. Hippophae rhamnoides leaves and fruit residues (left after oil extraction) can be used for feeding livestock, such as for poultry. The weight of livestock and poultry has been shown to increase considerably after being fed sea buckthorn.
Parts of the sea buckthorn plant are applied in traditional medicine, particularly in Russia and Northeast Asia. H. rhamnoides oil may be used to produce cosmetics, such as hand cream, shampoo or massage oils.
Cultivation Soil and climate requirements In nature H. rhamnoides is found growing profusely on a wide range of soil types, but does better in soils with a light physical structure, rich in nutrient compounds and with a pH near neutral (pH 6.5–7.5). Best growth occurs in deep, well drained, sandy loam with ample organic matter. Light, sandy soils have low water carrying capacity and are also low in nutrient mineral elements; so without the previous addition of organic matter, are not appropriate. Similarly inappropriate are clayey soils, with high density and water retention characteristics.