Seaberry (Sea Buckthorn)

(Hippophae rhamnoides)

Seaberry fruit
‘Titan’ fruit

Cultivars tested

‘Titan’, ‘Leikora’, ‘Hergo’, ‘Star of Altai’, ‘Golden Sweet’, ‘Garden’s Gift’, ‘Amber Dawn’, ‘Harvest Moon’, ‘Baikal’, ‘Radiant’, ‘Sunny’

Description and site preference

Type and size – highly variable, from small shrubs to medium-sized trees
Hardiness zone – 3-8
Exposure – full sun
Soil – any type with pH 5.5-7.5
Drainage – all but saturated soils

Economic factors

Years to harvest – 2-3
Maintenance – little, except pruning
Life of planting – long-term, depends on site and maintenance
Machine harvest potential – limited and very specialized
Suitable markets – processed (valued-added)

Seaberry plant with fruit
‘Hergo’ plants with fruit

Notable features

Nutritional highlights – high in vitamins and omega fatty acids ( Li and Schroeder, 1996)
Adaptability – high in full sun (does not tolerate shade)
Pest issues – very resistant, but Japanese beetle seem to prefer it
Invasive potential – low in most situations (see below)
Environmental benefits – pioneering, nitrogen fixing, stabilizes and enriches soil for other species

Integration characteristics

Shared management – intermediate to high (little required)
Shared equipment – low, very specialized harvest requirements
Shared processing – high, same as many other small fruits
Co-marketing – high, similar to many other value-added fruit products

Seaberry plant with fruit
‘Amber Dawn’ with fruit

Integration potential – high

Good potential companion crop in an integrated system.

History and background

The genus Hippophae rhamnoides belongs to the Elaeagnacae family. H.rhamnoides has a wide native range in the temperate and sub-arctic regions of the Northern Hemisphere with the exception of North America, where it was naturalized in Canada in the 1930s.

Seaberry is rich in genetic diversity as reflected in fruit size, shape, color and maturity, as well as in its plant size, form and shape. All seaberry plants share in common their thorniness, nitrogen fixing ability, dioecious nature and lack of an abscission layer, which makes fruit removal very difficult.

Nutritional values can vary among cultivars, but all have a rich and diverse nutrient profile. Seaberry is a superfruit, a term Carandale reserves for only the most outstanding fruits in their test plot. The nutritional and medicinal value of seaberry is largely unknown in North America, but has been known and exploited in Eurasia for centuries. The sea buckthorn industry has been thriving in Russia since the 1940s, when scientists there began investigating the biologically active substances found in the fruit, leaves and bark. The Russians developed products used by their cosmonauts and as a cream for protection from cosmic radiation. A more in-depth discussion about the medicinal and culinary uses of seaberry can be found below.

In Russia, Mongolia and Germany, thornless or nearly thornless seaberry cultivars have been bred, but these cultivars are not available in North America.

Observations at Carandale Farm

  • Carandale Farm is observing 11 cultivars of seaberry, and they all have adapted well in sunny locations. Plants in the shade test area that received less than one-half day of sun were dead or about to die with a two-year period. Those that were about to die recovered when transplanted to a sunny location.
  • As a non-native plant, seaberry has invasive potential. After observing their initial three cultivars for 10 years, Carandale has seen virtually no root suckering tendency in silt loam soils. They have not observed any spreading by seed, but the seaberry’s intolerance for shade would make this a non-issue in most environments.
  • Seaberry appears to be relatively pest-free with a few exceptions. The leaves seem to be a preferred food source for adult Japanese beetles.
  • Seaberry are so light sensitive that lower branches become unfruitful and die out entirely as they are shaded by higher foliage. This suggests a need for management pruning that could be integrated with a harvesting protocol.
  • Seaberry is high yielding and consistently productive.
  • The fruit exhibits these qualities: tart, but tartness varies among cultivars; a pleasing citrus flavor; juicy with a tough protective skin giving it the feel and appearance of a small water balloon. Fruit can be used in numerous ways.
  • Seaberry fruit do not have an abscission layer of cells, making them difficult to harvest conventionally.
  • Time of fruit ripening is cultivar-specific, ranging from July to November (or hard freeze).
  • Seaberry appears to be resistant to spring freeze damage.
  • Juice extraction should be done without heat. Steam extraction causes the juice to be off-color and off-flavor.
  • Pollination is by wind and gravity so plants do not need favorable conditions for insect and bee pollination for good fruit set. Male pollinator plants need to be dispersed uniformly throughout the planting at a ratio of 6-8 female plants to 1 male pollinator plant.
  • Seaberry could be a good companion crop, providing diversity and sharing of processing facilities.

Most retail nurseries offer only one or possibly two cultivar choices that are often unnamed, but German and Russian breeding programs offer dozens of selections. Many of these are being introduced by Jim Gilbert, founder of Northwoods Nursery/One Green World . There are few fruiting plant species that have more genetic diversity than Seaberry. Once it was determined that Seaberry did not pose an invasive threat at Carandale, they added additional cultivars to explore this diversity.

Planting in 2003

‘Titan’ is a Russian cultivar, ready to harvest in late August to early September. The fruit is large (by seaberry standards – about the size of a large pea or medium-sized blueberry) and easier to harvest by hand than most other selections. Fruit is bright orange, flavorful, less tart than most cultivars, attractive and aromatic. ‘Titan’ has been consistently fruitful. Carandale has noticed some undiagnosed cane die-out, which seems to be progressing slowly. ‘Titan’ has an upright growth habit, and unmanaged height is over 12 feet.

‘Leikora’ is a German selection that ripens in early to mid-September. The tear-drop shaped fruit has an intense, tart flavor. The medium-sized, bright orange fruit does not stand out for consumption, but it does have ornamental appeal. ‘Leikora’ has not been highly productive at Carandale. Lower branches are shaded by higher branches without pruning management.

‘Hergo’ is a German cultivar that ripens in mid- to late-September. The branches are densely covered by small, light orange fruit that is tart, flavorful and juicy. ‘Hergo’ is reported to be the most widely planted variety in German orchards where fruit is harvested mechanically by cutting then freezing the fruit-laden branches. Fruit is mechanically separated from the branches, being difficult to remove by hand.

Planting in 2006

These plants have not reached maturity. Some were re-transplanted from the shade trial in 2008 and have been slow to regain vitality.

‘Star of Altai’ (chuskaya cv.) is a Russian cultivar that bears attractive medium to large orange berries that are sweeter and earlier than other selections at Carandale. Plants are smaller than other cultivars of the same age. Fruit ripens late July to early August.

‘Golden Sweet’ is a German selection that is supposed to be a medium-sized shrub with large and very sweet fruit, but the specimens in the Carandale test plot do not meet this description. This may be a case of mis-labeling, but the plants in the test plot are the largest among their peers, and the fruit is medium-sized, yellow to light orange, with a unique, slightly flattened, globular shape.

‘Gardens Gift’ is a Russian cultivar that is second largest among its peers and bears an abundant crop of medium to large berries that ripen in late-August. Fruit is attractive, dark orange and aromatic, resembling that of ‘Titan’.

‘Amber Dawn’ is a Russian cultivar that did not adapt well. The one surviving plant is quite small. It produces small to medium yellow-orange fruit that is juicy and soft, lacking in flavor and appearance.

Planting in 2007

‘Harvest Moon’ is a selection from the prairie provinces of Canada. It was supposed to have fewer thorns, compact growth and be easier to pick, but the fruit quality and growth habit were almost identical to ‘Hergo’. ‘Harvest Moon’ is the only cultivar that has shown root suckering tendencies in silt loam soils. It will be removed from the test plot.

Planting in 2010

These were planted outside the test plot and have no protection from deer. This area is a certified organic, commercial-scale planting and part of a diversity trial including aronia, black currant and ‘Carmine Jewel’ bush cherry. In addition to ‘Hergo’ and ‘Titan’, Carandale is testing three other seaberry cultivars here. Plant size varied at planting based on available inventory from Northwoods Nursery. The planting is not yet in production, so the following descriptions are from catalog information.

‘Baikal Ruby’ is supposed to be a compact shrub not to exceed 6 feet, which could make it more compatible and require less pruning in a diverse planting. This characteristic is already becoming evident. The fruit is said to be coral-red, sweet and tasty. ‘Radiant’ is a Russian selection said to form a compact, attractive shrub growing 8 feet high. Fruit is said to be large, juicy and high in vitamin content. ‘Sunny’ is another Russian selection said to be a heavy producer of unusually sweet, high quality fruit that are easy to harvest and can be eaten fresh.

Discussion

Despite the beneficial attributes of seaberry, Carandale was concerned with invasive potential because the plant is not native and has a strong survival tactic (nitrogen fixation). After observations and an extensive literature review, Carandale has determined it will not be an invasive threat in their clay-based loamy soils high in phosphorous. They have not had issues with root suckering in the Russian and German cultivars. Only one cultivar (from Canada) has shown such tendency and will be removed.

There are reports from Alberta, Canada, that a single plant “is able to colonize an area of acres within a few years,” destroying biodiversity. Alberta has low-lying, moist riparian areas with a sandy soil, most likely low in fertility. There will be some environments (i.e those similar to Alberta) where seaberry could become invasive. But for the majority of situations, its pioneering ability to enrich the soil and reduce erosion will outweigh concerns of invasiveness. In Saskatchewan, Canada, seaberry is heralded as an ideal plant for soil erosion control, land reclamation, wildlife habitat enhancement and farmstead protection.

Seaberry is a easy plant to grow and requires very little care. Once established, it is drought-tolerant with few pest issues and virtually no fertility needs, though it may respond to a phosphorous application in low P soil. Nitrogen application is not recommended. It can adversely affect root nodulation (nitrogen fixing bacteria).

Seaberry is a light-demanding plant that dies if overshadowed by taller plants. Seedlings fail to grow in shade and are not competitive with other vegetation. Because of its intolerance for shade, it will never become an invasive threat in woodlands, unlike its cousin, the common European buckthorn. Mature seaberry plants can be drought-resistant, but seedlings require consistent moisture.

Seaberry is dioecious, requiring both male and female plants. Female plants are pollinated by male plants almost exclusively by wind or gravity because they do not have flowers to attract pollinators. The ratio of one male plant for every 6 to 8 female plants is considered adequate for optimal fruit production. Like many perennial fruiting plants, flower buds are differentiated during the previous growing season. Seaberry is cold-hardy (withstanding at least -40 degrees F) and resists freeze damage at fruit set. Carandale has never lost a crop due to spring freezes, even in unprecedented conditions of 2012 when a majority of fruit crops were damaged.

Due to genetic diversity, mature plants can range in size and form, ranging in size from a small bush less than 3 feet to a tree more than 60 feet. Most of the plant material used for commercial production will be multi-stemmed shrubs ranging from 6 to 15 feet tall. Carandale has not restrained height by pruning but will attempt to do so with newer plantings. There would be advantages to restricting plant height to about 6 feet: Seaberry is so light sensitive that as the shrubs grow, lower branches die from lack of sunlight. Also, a 6-foot limit would make harvesting much more efficient, and pruning could become an integrated part of a mechanical harvesting technique where fruiting branches are cut, frozen and stripped mechanically. This could be done every two years, which is the time it would take for new growth to occur and become fruitful

Seaberry is tasty and versatile. Food items include juice, sauces, jams, wine, tea, candy, ice cream and sorbet. Its tart, citrus-like flavor complements other foods, and it is a nutritional powerhouse rich in vitamins A, C, E and K. It also contains both saturated and unsaturated fatty acids and minerals. The leaves and tender branches of seaberry are a source of protein and other nutrients for wildlife and domestic animals. It’s being investigated for its ability to reduce the incidence of cancer and also for halting or reversing the growth of cancers. The juice is a component of many vitamin-rich cosmetic preparations used to reverse the effects of aging. Seaberry juice and its oils are said to heal burns, eczema and radiation injury. Also, a yellow dye is extracted from the skins of the fruit.

The greatest challenge and expense will be harvesting because of the lack of an abscission layer of cells. China had more than 200 processing plants for seaberry as of 2006 and will probably continue to dominate the international market. Carandale Farms recognizes that demand for locally grown products could make seaberry a lucrative fruit crop for commercial growers in spite of its harvesting challenges. Seaberry could be a great addition to provide diversity and share symbiotic relationships in a mixed commercial planting.

References

Plants for a Future information on Seaberry

Agriculture and Agri-Food Canada: Trees and Shrubs for Agroforestry in Canada.

Zeb, A. 2004. “Important therapeutic uses of Sea Buckthorn (Hippophae): A review.” Journal of Biological Sciences 4(5): 687-693 http://198.170.104.138/jbs/2004/687-693.pdf, accessed 6/26/13.

Li, TSC. 2002. “Product development of sea buckthorn.” p. 393–398. In: J. Janick and A. Whipkey (eds.), Trends in new crops and new uses. ASHS Press, Alexandria, VA.

Li, TSC and WR Schroeder. 1996. Sea buckthorn (Hippophae rhamnoides L.): A multipurpose plant. HortTechnology 6(4), 370-380. <http://horttech.ashspublications.org/content/6/4/370.full.pdf>, accessed 6/26/13.

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