The Cederberg in Bloom: Why Rooibos Grows Nowhere Else on Earth

There are places where a landscape does more than surround an ingredient.

It becomes part of it.

For Rooibos, that place is the Cederberg and the surrounding regions of South Africa’s Western and Northern Cape.

Every August – in spring – the Cederberg changes. Wildflowers emerge among ancient sandstone formations, fynbos covers the mountainsides, and a landscape that can appear harsh and dry through summer comes alive with tapestries of colour.

It is a beautiful place. But it is also a demanding one.

And somewhere within that landscape, Rooibos has evolved to thrive.

 

Why does Rooibos grow here?

Rooibos (Aspalathus linearis) is indigenous to the Fynbos Biome of the Cape Floristic Region – one of only six floral kingdoms in the world. It is the smallest and, uniquely, the only one contained entirely within a single country: South Africa. Despite its size, it is one of the most botanically diverse regions on Earth, with thousands of plant species and exceptionally high levels of endemism (SANBI, n.d.).

This is the extraordinary environment in which Rooibos evolved.

The conditions are extraordinarily specific: a Mediterranean climate, with cool, wet winters followed by long, hot, dry summers, combined with coarse, sandy, acidic and nutrient-poor soils derived largely from the Table Mountain Sandstone Complex (European Commission, 2022).

For many crops, these conditions would be challenging.

For Rooibos, they are home.

Over thousands of years, the plant has adapted to this particular combination of climate, soil, water availability and seasonal change, and the environment doesn’t simply determine where Rooibos grows. It has helped shape the plant itself.

And you can see that in Rooibos from the ground up.

 

A root system built for drought

During a Cederberg summer, water becomes precious.

Rooibos responds with a root system remarkably suited to its environment.

The plant develops a long taproot that can reach as deep as two metres and more into the soil, alongside a network of finer lateral and cluster roots closer to the surface (European Commission, 2022; MacAlister et al., 2020a).

Each serves a specific purpose.

The taproot system allows Rooibos to reach moisture deeper in the soil, while finer roots near the surface make use of even the smallest amounts of available moisture.

Even more remarkably, research has shown that Rooibos increases its root-to-shoot ratio under drought conditions and can produce longer, thinner roots, effectively investing more of its resources below ground when water becomes scarce (MacAlister et al., 2020a). Recent research into soil-water dynamics has also suggested that the fine cluster roots concentrated around 10–30 cm depth may help the plant make use of miniscule quantities of moisture that become available in the drying soil profile during summer (van Schalkwyk et al., 2023).

In other words, Rooibos does not simply endure a dry summer.

Its architecture is built around it.

 

Even the leaves tell the story

Look closely at a Rooibos plant, and its leaves tell yet another story of adaptation.

Small, slender and needle-like rather than broad and flat, they are perfectly suited to a landscape where every drop of water matters. A relatively thick cuticle helps protect the leaf from water loss, while the position of its stomata allows the plant to carefully regulate how much moisture escapes (Kotina et al., 2012).

In the heat of a Cederberg summer, this matters.

The narrow leaves expose less surface area to the intense sun, while the plant can close its stomata and reduce transpiration when water becomes scarce (Lotter et al., 2014; MacAlister et al., 2020a).

It’s a small leaf, but a clever one.

And there is another fascinating consequence of Rooibos’ unique relationship with its environment…

 

When the going gets tough

Plants cannot simply move away from heat, drought or poor soils.

They have to respond biologically.

One of the ways Rooibos responds to environmental stress is through changes in its secondary chemistry, including the production of phenolic compounds.

Research on Rooibos exposed to drought has found increased concentrations of polyphenols in the leaves – compounds that are thought to play a protective role for the plant under environmental stress (MacAlister et al., 2020a). Research into temperature stress has similarly found high phenolic content in heat-acclimated Rooibos plants (MacAlister et al., 2020b).

And here is where the story becomes particularly interesting for us.

The very compounds that help protect the plant are also some of the compounds we value most in Rooibos.

Rooibos is naturally rich in polyphenols, including aspalathin, a distinctive flavonoid particularly characteristic of the plant (Joubert & de Beer, 2011). These compounds are valued for their antioxidant properties and are an important part of the growing interest in Rooibos as a naturally caffeine-free source of bioactive plant compounds. The hot, dry maturation period characteristic of the Rooibos-growing region is closely associated with the accumulation of these phenolic compounds, a relationship recognised in the European Union’s PDO specification for Rooibos (European Commission, 2022).

Rooibos develops chemistry to help meet the demands of its environment – and those same compounds are part of what makes the plant so valuable to us.

There is something wonderfully appropriate about that.

Rooibos does not merely survive its environment. Its environment helps define it.

 

A plant shaped by place

This is why the idea of “single origin” means something particularly tangible when we talk about Rooibos.

Rooibos is not simply a crop that happens to be produced in South Africa.

Its identity is tied to a particular ecological region.

Its roots are adapted to its soils.

Its leaves are adapted to its climate.

Its growth cycle follows the seasons.

Its chemistry responds to the conditions in which it matures.

And surrounding all of this is the extraordinary Fynbos ecosystem – one of the world’s most botanically diverse regions.

The relationship is not simply between a plant and a farm.

It is between a plant and a landscape.

 

Heritage written into the landscape

This is also where the story becomes bigger than botany.

Rooibos has been part of the cultural and agricultural heritage of the region for generations.

Traditional knowledge of where it grows, and how to cultivate, harvest and process it, has developed alongside the landscape itself. That knowledge is part of what connects Rooibos to its place of origin. It has been built over generations through observation, experience and an understanding of the land. It is knowledge that cannot simply be separated from the environment in which it developed.

And neither can Rooibos.

This is one reason the recognition of Rooibos / Red Bush as a Protected Designation of Origin (PDO) is so meaningful. The European Union’s PDO specification recognises the direct relationship between the geographical area, its climate and soils, and the specific characteristics and composition of Rooibos. The protected geographical area spans defined municipalities in the Western Cape and Hantam Municipality in the Northern Cape, encompassing the wider Rooibos-growing region (European Commission, 2022).

PDO gives legal recognition to what generations of knowledge have long understood: Rooibos is inseparable from its place.

And that is what provenance really means.

Not simply knowing where an ingredient comes from, but understanding the land, people, knowledge and conditions that have shaped it.

For Heritage Month, that feels particularly worth remembering.

 

Heritage that can be shared

This Heritage Month, we’re reminded that heritage lives in the land, in knowledge passed from one generation to the next, and in the things we continue to cultivate and share with the world.

Every time South African Rooibos reaches a new market, it carries a little of its heritage with it – shaped by the land, nurtured by generations of knowledge and rooted in South Africa.

At Carmién, we’re immensely proud to work with an ingredient whose identity is inseparable from the landscape that shaped it.

Because some ingredients can be grown elsewhere.

Rooibos belongs here.

It was shaped by this place. Our place.

It is, and always has been, intrinsically woven into the story of South Africa.

References

• European Commission (2021) Commission Implementing Regulation (EU) 2021/865 of 28 May 2021 entering a name in the register of protected designations of origin and protected geographical indications — “Rooibos/Red Bush”. Official Journal of the European Union, L 190, pp. 88–93. EUR-Lex – Rooibos/Red Bush PDO registration
• European Commission (2022) Publication of the amended single document following the approval of a minor amendment pursuant to the second subparagraph of Article 53(2) of Regulation (EU) No 1151/2012 — “Rooibos / Red Bush”. Official Journal of the European Union, C 89/07, pp. 22–26. EUR-Lex – amended Rooibos/Red Bush PDO specification
• Hawkins, H.-J., Malgas, R. & Biénabe, E. (2011) ‘Ecotypes of wild rooibos (Aspalathus linearis (Burm. F) Dahlg., Fabaceae) are ecologically distinct’, South African Journal of Botany, 77(2), pp. 360–370. doi: 10.1016/j.sajb.2010.09.014. Article – South African Journal of Botany
• Joubert, E. & de Beer, D. (2011) ‘Rooibos (Aspalathus linearis) beyond the farm gate: From herbal tea to potential phytopharmaceutical’, South African Journal of Botany, 77(4), pp. 869–886. doi: 10.1016/j.sajb.2011.07.004. Article – South African Journal of Botany
• Kotina, E.L., Stepanova, A.V., Tilney, P.M. & Van Wyk, B.-E. (2012) ‘The pharmacognostic value of leaf and stem anatomy in rooibos tea (Aspalathus linearis)’, South African Journal of Botany, 82, pp. 129–133. doi: 10.1016/j.sajb.2012.07.002. Article – South African Journal of Botany
• Lotter, D., Valentine, A.J., Archer Van Garderen, E. & Tadross, M. (2014) ‘Physiological responses of a fynbos legume, Aspalathus linearis to drought stress’, South African Journal of Botany, 94, pp. 218–223. doi: 10.1016/j.sajb.2014.07.005. Article – South African Journal of Botany
• MacAlister, D., Muasya, A.M., Crespo, O., Ogola, J.B.O., Maseko, S., Valentine, A.J., Ottosen, C.-O., Rosenqvist, E. & Chimphango, S.B.M. (2020a) ‘Stress tolerant traits and root proliferation of Aspalathus linearis (Burm.f.) R. Dahlgren grown under differing moisture regimes and exposed to drought’, South African Journal of Botany, 131, pp. 342–350. doi: 10.1016/j.sajb.2020.03.003. Article – South African Journal of Botany
• MacAlister, D., Muasya, A.M., Crespo, O., Ogola, J.B.O., Maseko, S., Valentine, A.J., Ottosen, C.-O., Rosenqvist, E. & Chimphango, S.B.M. (2020b) ‘Effect of temperature on plant growth and stress tolerant traits in rooibos in the Western Cape, South Africa’, Scientia Horticulturae, 263, 109137. doi: 10.1016/j.scienta.2019.109137. Article – Scientia Horticulturae
• South African Department of Environmental Affairs (2015) Report of the study conducted on the traditional knowledge associated with the rooibos and honeybush species in South Africa. South African Government – Traditional knowledge associated with Rooibos and Honeybush
• South African National Biodiversity Institute (SANBI) (n.d.) ‘Fynbos Biome’, PlantZAfrica. SANBI – Fynbos Biome
• van Schalkwyk, R., Hoffman, J.E., Hardie, A.G. & van Zyl, J.L. (2023) ‘Soil water dynamics and biomass production of young rooibos (Aspalathus linearis) plants’, Scientific Reports, 13, 15154. doi: 10.1038/s41598-023-41666-5. Scientific Reports – Soil water dynamics and biomass production of young Rooibos plants