Jim Todd, Transition Crop Specialist and Melanie Filotas, Specialty Crops IPM Specialist
Sea buckthorn (Hippophae rhamnoides L.), also known as Siberian pineapple, Sea Berry, Sandthorn or Swallowthorn, is a deciduous shrub native to north western Europe, central Asia, western and northern China and the northern Himalayas. Sea buckthorn is a remarkably hardy bush, typically 0.5 to 6 m in height that rapidly develops an extensive root system capable of fixing nitrogen. Thus, it is suitable for growth on marginal soils, eventually improving them to where they can support the growth of other plants. It is quite tolerant of salt-spray adjacent to highways. Sea buckthorn has been used for: Soil erosion control and land reclamation projects, wildlife habitat enhancement and farm stand protection and as an ornamental bush.
Historically, sea buckthorn was used in ancient Greece as a fodder for horses to promote weight gain and a shiny coat. In fact, the generic Latin name “Hippophae” literally translates to “shiny horse”. Sea buckthorn has been used for centuries in both Europe and Asia as food; and for its pharmaceutical properties. Currently, juice from sea buckthorn berries is a common drink in many parts of Asia and Europe. The juice is very high in protein, vitamins C and E, and organic acids. The leaves, either fresh or dried, can be steeped to yield a nutritional tea, and the leaves, young branches and fruit pulp can be used as animal fodder. Sea buckthorn also has a long history of medicinal use. Topical application of sea buckthorn oil has been reported for skin therapy including sun, heat, chemical and radiation burns, eczema and poorly healing wounds. Russian cosmonauts used sea buckthorn cream for protection from cosmic radiation. Oil from the sea buckthorn fruit is rich in vitamin E, carotenoids, phytosterols and essential fatty acids, all of which have beneficial medicinal properties for the treatment of internal and topical maladies.
The Sea buckthorns are deciduous shrubs that typically range from 0.5 to 6 m in height with equivalent spread, but may reach up to 18 m in central Asia. The staminate trees are more erect than the spreading pistillate trees. It naturally tends to sucker forming thickets if not properly maintained. They can survive temperatures as low as – 40°C, and are both drought and salt tolerant. Sea buckthorns require full sunlight for good growth and cannot tolerate shady conditions near larger trees. The branches are dense, stiff, and very thorny with both terminal and axillary twig spines. The linear or lanceolate shaped leaves, which are 3 to 8 cm long and less than 7 mm wide, are dark grey-green on the upper surface and a distinct pale, silvery-grey on the lower surface. Sea buckthorn is dioecious, with separate male and female plants. Flowers emerge prior to the leaves, are localized to the 2nd year-old wood, and occur in small racemes in the leaf axils along the entire length of the branch. Pollination of the female flowers occurs in mid-May, and is entirely dependent on wind to spread pollen from the male flowers. Fruit ripening occurs about 100 days after pollination. Sea buckthorn fruit can vary in both shape and colour, but are typically globose to egg-shaped berries ranging from yellow to bright orange in colour. The combination of fruit shape and size, together with the contrast between the colour of the fruit and leaves, contributes to the ornamental value of this plant.
Sea buckthorn is a woody shrub to small tree hardy to Zone 3 (- 40°C), that can be propagated from either seed or by cuttings. Sea buckthorn is adapted to a wide variety of soils, and will grow on marginal land including sandy, gravely soils with poor nutrient and water retention capacities. Sea buckthorn thrives in full sunlight, on well drained, light to medium sandy loam having a pH between 6-7. Although drought tolerant, and moderately tolerant to saline soils, a minimum of 400 mm of annual precipitation is required to ensure good fruit yield.
Figure 1. 3 year old sea buckthorn trees.
Orchard design is dependent on whether the fruit will be harvested mechanically or by hand. Typical orchards have about 600 to 1000 plants per acre, with 1 male for every 7 female plants. When only a few trees are grown, the berries can be readily harvested by hand, requiring about the same amount of effort as harvesting raspberries. Although the thorniness of the sea buckthorn bushes can be a problem, young plants may be relatively thorn free. Some thornless varieties are currently available, and future breeding efforts should increase their numbers. As the number of trees in the orchard increases, so does the work required for harvesting the berries. Figures from China indicate that up to 1500 person hours per hectare are required for hand harvesting. Successful commercial operation of a sea buckthorn orchard will ultimately require the development and implementation of some type of mechanical harvester. Several types have been developed, including a vibratory shaker invented in Saskatchewan. The difficulty of removing the fruit from the tree diminishes as the season progresses. Unfortunately, fruit quality also decreases over this same period, so optimum times for harvest will need to be identified for individual growing areas. As with any crop grown for nutraceutical, medicinal or culinary use, post-harvest handling of sea buckthorn berries should conform to approved “Good Agricultural Practices” standards. After cleaning, the berries should be processed as soon as possible, but may be either stored at low temperature (4 to 6°C), or flash frozen if immediate processing is not feasible. The shelf life of berries stored at low temperature can be up to 2 weeks. Berries maintain their shape when thawed after freezing.
Figure 2. Berry yield from 3 year old sea buckthorn trees. Maximum fruit set occurs in trees 4 years and older.
As with any alternative crop, new growers should educate themselves on the cost of production and the market potential of sea buckthorn. Furthermore, prior to making any claims about the nutraceutical or medicinal properties of sea buckthorn, growers must ensure that these claims fall within the regulations established by the Natural Health Products Directorate of Health Canada.
General notes on Sea Buckthorn pests and their management
At present, relatively few serious insect or disease pests of sea buckthorn have been reported. However, pest problems are likely to increase if acreage increases. Important diseases of sea buckthorn include Verticillium wilt, fusarium wilt, scab and damping off. The most damaging insect noted on sea buckthorn so far are aphids, which prefer shoot tips, stunting tree growth and causing leaves to turn yellow, shrink along the centre vein and drop. Thrips, earwigs and mites have also been noted on sea buckthorn in Canada. A variety of other insects have been reported from sea buckthorn. Additionally, birds, deer, mice and other rodents will also feed on sea buckthorn, occasionally causing serious damage.
Weed control is another important consideration in sea buckthorn orchards. It is commonly thought that this is most important in newly planted orchards, where lack of adequate weed control has been cited as an important cause of seedling mortality. Weeds can also harbour insects, diseases and other pests, such as mice. In some sea buckthorn orchards in Ontario started from one to two year-old trees, weed growth did not appear to have serious detrimental effects on the plant. Still, growers may need to intensively control weeds for 4-5 years, until trees are large enough to shade out weeds. Because no herbicides are registered for use on sea buckthorn orchards in Ontario, this is primarily accomplished by mechanical or hand cultivation between and within rows.
One important factor that any potential producer of sea buckthorn must consider is the lack of control products that can be applied to this crop should pest problems arise. At present, there are no pesticides registered for use on sea buckthorn orchards in Canada. This means that growers will have to rely heavily on other integrated pest management options to keep pest populations at bay. This could include;
- careful site selection,
- choice of pest tolerant cultivars (when available),
- examining planting stock upon arrival for presence of insect or disease,
- an emphasis on sanitation (removing all potential sources of infestation from an orchard – for example removing and burning dead trees),
- removal of possible alternate/overwintering hosts of pests (eg plant debris, weeds, etc.),
- frequent monitoring of orchards to detect presence of pests,
- optimizing tree health to promote resistance to pests,
- maintaining an environment that supports the presence of beneficials (natural enemies such as predatory insects which help suppress pest populations)
It’s important to note that most of these techniques are pre-emptive – focusing on preventing pest populations from establishing in the orchard in the first place. This means that sea buckthorn growers should be thinking about potential pests and how to avoid infestations right from the start, before they even plant their trees.
Information on this and other specialty crops can be found on the Ontario Ministry of Agriculture and Food website under: Specialty Cropportunities (http://www.omafra.gov.on.ca/CropOp/en/index.html).
The above information was compiled from a number of resources including:
Li, T.S.C. and C. McLoughlin. 1997. Sea Buckthorn Production Guide. Canada Sea buckthorn Enterprises Limited.
Li, T.S.C and Beveridge, T.H.J. 2003. Sea Buckthorn (Hippophae rhamnoides L.): Production and Utilization. NRC Research Press, Ottawa. (www.monographs.nrc-cnrc.gc.ca)
Sea buckthorn. An information sheet created by Joseph Widdup, under a joint venture between the University of Saskatchewan Department of Plant Science and the Saskatchewan Fruit Growers Association.
Small, E., P.M. Catling, and T.S.C. Li. 2002. BLOSSOMING TREASURES OF BIODIVERSITY: 5. Sea Buckthorn (Hippophae rhamnoides)-an ancient crop with modern virtues. Biodiversity Vol 3(2)