New Zealand plants are unique, and amongst the best in the world. As an island nation situated a long way away from most other places, in the 55 million years since New Zealand separated from Gondwanaland, its native plants had a long time to evolve before humans arrived, and it’s therefore not surprising that many have some special properties.

Aside from indigenous species, numerous other plants also seem to have special characteristics when grown in the New Zealand environment, and we are fortunate to live in a country where such a wide variety of plants can be grown relatively easily.

Reasons for this are many, but probably include the relative youth of our landmass, the richness of our soils carved from volcanoes, rainforests and other inputs from nature, and our diverse geography and microclimates. There are few countries in the world where one can be sunbathing on the beach in the morning, and skiing in cold alpine temperatures a few hour’s drive away, in the afternoon.

The bioactive and medicinally active compounds in plants, are known in plant physiology and phyto-pharmacology as secondary metabolites. These include many different classes of chemical compounds such as alkaloids, flavonoids, essential oils and phenolic acids, whose functions within the plant are mainly to protect it against harmful influences or predators.

Plants growing in a stressful drought environment will produce higher levels of secondary metabolites than plants which are less stressed. Next time you are out in the bush, look out for kawakawa plants and you may notice that many of the heart shaped leaves contain lots of holes, courtesy of the kawakawa looper moth caterpiller. This is a good example of a plant thought to have greater medicinal properties from secondary metabolites, produced as a defense mechanism against the caterpillars.

One reason why so many plants grow so quickly and well in New Zealand, is thought to be attributable to the hole in the ozone layer in the atmosphere above us. In response to high UV-B light, New Zealand plants have to put greater energies into producing secondary metabolite compounds to protect themselves, many of which have medicinal properties.

New Zealand is also fortunate to have a reasonably strong biosecurity system, together with a relative abundance of water by world standards. Water supplies as well as soil health are critical parameters in producing healthy plants, both for food and for medicines.

New Zealand’s fruit and vegetables are widely known to have a great taste and high quality. This superior raw material quality has contributed significantly to our growing reputation as a country with some of the best cuisine in the world. The kiwifruit, hops, wine and berry industries have flourished and performed well for New Zealand in recent decades, all fundamentally due to their high quality characteristics. Thanks to a great deal of trial and error, hard work, investment of scientific knowhow and money, and most of all a whole lot of Mother Nature. These plant-based products are highly sought after in export markets, and as consumers we are privileged to have a wide selection of excellent quality foods and beverages available to us!

Medicinal plants (herbs) have also shown excellent quality parameters when grown in the New Zealand environment, and some examples of these follow.

Korean and American ginseng (Panax ginseng and Panax quinquefolium), seem to like it here, as very high levels of active ginsenosides have been achieved in ginseng roots. Thanks to work by the former Crop & Food Research (now Plant & Food Research) and a small number of dedicated growers (it takes many years and significant investment to establish and grow ginseng commercially), much has been learnt about ideal growing and harvesting methods, including how to grow it within Pinus radiata forests.

Leaves of ginkgo (Ginkgo biloba) are best known to help prevent dementia and other age-related disorders, as well as improve memory in healthy individuals. Levels of the active ginkgo flavone glycosides and terpenoids in New Zealand grown material are higher than those produced by trees grown in China, where most of the world’s ginkgo is sourced. This enables therapeutic levels to be achieved with a lower dose.

As with ginseng, golden seal (Hydrastis canadensis) is slow-growing and endangered in its natural habitat, yet global demand is high due to research validating its use as an antibacterial agent. This valuable medicinal plant was grown commercially by a couple of growers in New Zealand in the 1990’s, again with agronomy research support from Crop & Food Research. Much was learnt about how to grow it under local conditions, and laboratory tests showed the rhizomes contained very high levels of the active compounds hydrastine and berberine.

Many other medicinal herbs grown in New Zealand have been found by research studies or routine tests by manufacturing companies, to have very high levels of active phytochemicals. These include echinacea (alkylamide levels in the roots), arnica (another increasingly endangered species but New Zealand grown flowers containing high concentrations of sesquiterpene lactones), green tea (high epigallocatechin gallate and theanine levels), and valerian (high valerenic acid levels in the root and rhizome). The New Zealand blackcurrant industry has also grown rapidly over the past 20 years, catalysed by research showing significantly higher levels of antioxidant anthocyanidins in NZ berries than those grown in other countries, and anti-aging and cognitive-enhancing actions. Superior flavour profiles, and higher levels of vitamin C, have also been reported.

In summary, an appraisal of the performance of these “new” and more established medicinal plant crops in our New Zealand environment, shows that in all cases key quality parameters are significantly above average and in some cases are at the top of their field, when compared to the same species grown offshore.

New Zealand grown herbs are amongst the best in the world. Best for the health of ourselves, our pets and animals, our economy, our soils and waterways.

Kaitiakitanga in Māori, is about ensuring an intergenerational stewardship of the land, sea and waterways. Encouraging the growing of more both native and non-native medicinal plants in our own country rather than relying on cheap-labour countries to supply the bulk of our increasing needs, makes good sense.

 

Phil Rasmussen