Plant of the Week – Hippophaë rhamnoides – Sea buckthorn – 14th December 2020

This blog is inspired by a late autumn trip to Longniddry Bents to collect the yellow-orange berries of Hippophaë rhamnoides for a seasonal pot of jelly – to go with our Christmas turkey. The sight of the berries, a foil for the sun as it set, was one of the botanical harbingers of our changing seasons. Sea buckthorn is a plant of many parts: it is known for its medicinal properties, for its ecological contributions to dune stabilisation, as a supply of food for birds flying along their autumn migration route, and above all the striking berries set against the blue-grey leaves.

Figure 1. Hippophaë rhamnoides, Aberlady Bay. ©Chris Jeffree

The word “Hippophaë” originates from the Greek word “hippo”, meaning horse and “phaos” – to shine, after the ancient Greeks noted that horses that grazed upon it exhibited shiny coats.  Carl Linnaeus must have known this when he recorded this plant (Family Eleagnaceae) for the first time and established the genus Hippophae, including species H. rhamnoides L.

This deciduous, dioecious (two sexes), branched, spiny plant can grow between 2 and 4 metres in height. It has alternate, narrow, and lanceolate leaves – glaucous green on top and silvery underneath, covered in peltate scaly hairs, which are a feature of the Eleagnaceae. It is wind-pollinated; hence the flowers are small, unremarkable and apetalous. The male flowers appear before the leaves, while the female flowers appear with the leaves. The plentiful ripe berries on the female plants are soft, orange-red, each containing a single seed. The plant is dispersed by birds. Birds also use the shrub for nesting, feeding, roosting and taking cover from predators among its spiny thorns. The berries produced in autumn and winter may be an important food source, especially for migrant birds, such as fieldfares and redwings, while at other times of year many species of birds feed upon the insects living in it.

Hippophae rhamnoides has been divided into several subspecies worldwide, but the British populations all belong to H. rhamnoides subsp. rhamnoides (Stace, 1997). Its presence in the UK has ebbed and flowed. Archaeological studies confirm its extensive presence here on sands and gravel in Late-glacial times. Then the populations shrank due to competition with trees (Pennington, 1989). A distribution map in Pearson and Rogers (1962) shows only about 40 native populations along the East coast of England and South- East Scotland. From these local foci, the species has spread to become introduced, naturalised and even invasive in some places. Much of its spread is due to its deliberate planting as a pioneer to stabilise dunes and reduce soil erosion. Its expansion (compare Figures 2 and 3) may also be due to reduced nibbling by rabbits – following the outbreaks of myxomatosis in the 1950s and 60s (Dargie, 2002).

The plants have vigorous, extensive horizontal system of roots which are useful for stabilising the sand, but are also responsible for their invasiveness. The rhizosphere around the roots is teeming with beneficial microorganisms. The roots bear nodules, which house the symbiotic actinomycete Frankia, endowing them with the capacity to fix atmospheric nitrogen at rates similar to those of rhizobial legumes (Jike and Xiaoming, 1992). There are also arbuscular mycorrhizal fungal associates which deliver phosphates (Gardner et al, 1984).  The plant can spread vegetatively by suckering, so that each seed-borne genotype can spread over a large area. The plants are very aggressive and can grow in unpromising sites, such as those shown in Figure 5, germinating (or maybe suckering?) on tarmac.

From http://www.brc.ac.uk/plantatlas/plant/hippophae-rhamnoides

Figure 4. H. rhamnoides in Aberlady Bay ©Chris Jeffree

In Scotland and Ireland (where the species is not native) it is negatively perceived for both ecological and practical reasons. The nitrogen-enriched soils around the plants attract nitrophile weeds such as nettle, thistle and goosegrass, while on golf courses dense sea buckthorn stands take up areas that could be usefully converted to links – and no doubt they also consume a multitude of lost balls. In Aberlady Bay in East Lothian volunteer groups have been set up to remove it for ecological reasons. Interestingly, around that part of East Lothian the locals call it the baked bean bush (Aberlady Bay Volunteers, no date). 

Figure 5. Seedling (or sucker?) forcing its way through tarmac, Queensferry. ©Chris Jeffree

The ecological impacts of the species have been investigated by Dargie (2002). He believes that its negative ecological impacts in Scotland have been overplayed and that the perceived threats need to be revised. He suggests “the establishment and management of a dynamic equilibrium where colonising stages of the scrub, as well as more permanent mature stands, can be promoted without detriment to grey dune, yellow dune or humid dune slack features of interest”.

While some people see the plant as a scourge, others see it as a ‘wonder-food’, ‘holy fruit’, ‘liquid gold’, ‘super-berry’ (Figure 6).

Image date, November 2020

Indeed, analyses have shown the berries to be a veritable repository of health- giving phytochemicals. About 190 bioactive compounds have been listed (Patil and Chaudhary, 2016). Most plentiful are the antioxidants, including flavanols, tocopherols, tocotrienols and carotenoids (Tabasum et al., 2018). The vitamin C content in the berries is 400mg/100 g of berries (Gutzeit, 2008), which makes them about 7 -10 times as rich as a similar weight of orange. The berries are also packed with Vitamin K, Vitamin B complex, coumarins and triterpenes (Suryakumar and Gupta, 2011) and valuable fatty acids – including Omega 7 (Sola Marsinach, 2019). The berries have been used as a popular remedy in traditional Indian Ayurvedic and Chinese pharmaceutics, and have been used medicinally in cancer therapy, cardiovascular diseases, treatment of gastro-intestinal ulcers, skin disorders, and as a liver protective agent (Zeb, 2004). Creams, cosmetics and shampoos made from it claim to rejuvenate, invigorate and restore skin and hair.

The berries and indeed the whole plant are used in animal husbandry and veterinary medicine. Laying hens supplemented with sea buckthorn at the rate of 2 and 3 g/kg improved the egg quality parameters and egg cholesterol (Chand et al., 2018). The traditional observations of shiny coats in horses, have been put into modern veterinary practice with several different sea buckthorn preparations specifically for equine use. Why not? After all legend has it that it worked for the mythical Pegasus, whose powers of flight were reputed to have been enabled due to the consumption of sea buckthorn.

Trendy growers, recognising the potential of the plant as a super-food, have bred new cultivars with larger fruit and longer stems for easier picking with fewer and softer thorns. More thorny varieties have also been bred for hedging. These usually serve a dual purpose as the fruit-laden branches can be snipped in the autumn, the berries utilised, and the hedges shaped. Permaculture enthusiasts see sea buckthorn as a pioneer species which, with its nitrogen-fixing properties, enriches the soil for other species in the food forest. However, anyone tempted to try sea buckthorn cultivation must remember that only the female plants bear fruit. Female plants can be multiplied from cuttings, but males need to be grafted on, or included in the planting.

The harvested berries can be jammed or jellied, or frozen and then eaten as a snack – a sort of natural chewable vitamin C pill. The juice can also be pressed out, diluted with water or apple juice, sweetened with honey and frozen in ice cube trays; a small cube makes an excellent addition to a gin and tonic. Cheers!

References

Aberlady Bay Volunteers (no date). https://www.edubuzz.org/aberladybay/scrub-removal/ (retrieved 2/12/2020)

Dargie, T. (2002). https://www.researchgate.net/publication/342721314_ECOLOGICAL_ASSESSMENT_OF_Hippophae_rhamnoides (retrieved 2/11/2020)

Chand, N., Naz, S., Irfan, Khan, R.U. and  Rehman, Z. (2018). Effect of Sea Buckthorn (Hippophae rhamnoides L.) Seed Supplementation on Egg Quality and Cholesterol of Rhode Island Red×Fayoumi Laying Hens. Korean J. Food Science Animal Resources. 38, 468–475.

Gardner, I. C., Clelland, D.C. and Scott, A. (1984). Mycorrhizal Improvement in Non-Leguminous Nitrogen Fixing Associations with Particular Reference to Hippophaë Rhamnoides L. Plant and Soil, 78, 189–199.

Gutzeit, D., Baleanu, G., Winterhalter, P. and Jerz, G. (2008). Vitamin C content in sea buckthorn berries (Hippophaë rhamnoides L. ssp. rhamnoides) and related products: a kinetic study on storage stability and the determination of processing effects. Journal of Food Science, 73, 615-620.

Jike Z, Xiaoming Z (1992). Progress of study on Frankia in nodules of Seabuckthorn. Hippocampus 2, 4–10.

Patil, S.G., Chaudhary, A.K. (2016). Unexplored therapeutic treasure of Himalayan sea buckthorn berry: An opportunity for rejuvenation applications in Ayurveda. International Journal of Green Pharmacy, 4, 164-171.

Pearson, M.C. and Rogers, J.A. (1962), Hippophae rhamnoides L. Journal of Ecology. 50, 501-513.

Pennington, W. (1969) The History of British Vegetation. Hodder and Stoughton Ltd.

Solà Marsiñach, M. and Cuenca, A.P. (2019). The impact of sea buckthorn oil fatty acids on human health. Lipids in Health and Disease 18, 145.

Stace, C.A. (1997). New Flora of the British Isles (2nd ed). Cambridge University Press.

Suryakumar, G. and Gupta, A. (2011). Medicinal and therapeutic potential of Sea buckthorn (Hippophae rhamnoides L.). Journal of Ethnopharmacology, 138, 268-278.

Tabascum, F., Nazir, A., Naseer, B. and Hussain, S.Z. (2018) Sea Buckthorn (Hippophae rahamnoides): a repository of phytochemicals. International Journal of Pharmaceutical Science and Research 3, 9-12.

Zeb A. (2004). Important therapeutic uses of sea buckthorn (Hippophae): a review. J Biol Sci. 4, 687–693.

© Maria Chamberlain

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