23 July 2019

Meet the oldest pot plant in the world

Our Eastern Cape giant cycad (Encephalartos altensteinii) arrived at Kew in 1775. Here's its unique story.

By Katie Avis-Riordan

The Eastern Cape giant cycad (Encephalartos altensteinii) in the Palm House

OAP (Old Age Plant)

Among the lush green leaves and steamy heat of our tropical Palm House lives one remarkable, record-breaking plant – the Eastern Cape giant cycad (Encephalartos altensteinii).

Weighing more than a tonne and measuring over four metres in height, this cycad is the oldest pot plant in the world.

The amazing specimen first arrived here in 1775 after Kew’s first plant hunter, botanist Francis Masson, brought it back to the Gardens. He collected the plant in the Eastern Cape province of South Africa, the species’ country of origin.

Put on board a wooden sailing ship, the palm-like plant’s long journey from South Africa to London would have taken several months.

During the travels the cycad was strapped to the deck to give it access to rainwater and sunlight, before being transported by barge along the Thames to Kew.

The Eastern Cape giant cycad (Encephalartos altensteinii) at Kew in 1895
The Eastern Cape giant cycad (Encephalartos altensteinii) at Kew in 1895 © RBG Kew

One cone wonder

Though the Eastern Cape giant cycad has been living at Kew for over 240 years, the plant has only ever produced one single cone during its time here.

This was in 1819 and was witnessed by naturalist Sir Joseph Banks, Kew’s first unofficial director, the year before his death.

Slow grower

Now sitting in a large plant pot, the long-lived cycad moved into the Palm House in 1848 and only grows at an average rate of 2.5 cm per year.

In its younger years, this species of ornamental cycad appears trunkless and has pinnate, palm-like green leaves which are whorled and form a dense upright crown.

As the plant continues to grow, a stout trunk starts to develop, rising to four or five metres tall in maturity. The single stem stands up straight until older age when it begins to recline.

Like some senior citizens, our elderly Eastern Cape giant cycad has to lean on props to remain standing. Without them the plant cannot support its own weight.

It’s not only our specimen that’s an old timer though. Cycads have been around since before the dinosaurs walked the Earth. The prehistoric plants were widespread over 250 million years ago.

The Eastern Cape giant cycad (Encephalartos altensteinii) in the Palm House
The Eastern Cape giant cycad (Encephalartos altensteinii) in the Palm House © RBG Kew

Caring for the giant

Perfectly at home in the Palm House with lots of warmth, light and humidity, the Eastern Cape giant cycad is cared for by our team of horticulturists in several ways:

  • Watering the plant varies throughout the year with more watering needed during the summer months. Naturally the cycad would grow in dry areas that receive a period of summer rainfall.
  • The plant doesn't require any pruning other than the removal of dead leaves.
  • Its position in the southern end of the Palm House is one of the sunniest spots in the glasshouse, so it receives a good amount of light.
  • One of the biggest challenges of looking after this plant is getting the level of irrigation right. It's in a very large pot, so it's better to water thoroughly and less often than a little bit at a time. The plant does not change visually a great deal over the course of a year and is very slow growing, producing new leaves sporadically every few years. This makes it difficult to know how much water it's using up.
  • In July 2009, the cycad was lifted and repotted into a new container made from sapele wood. This took a team of nine to complete. It was also resoiled using a specially prepared compost.

‘Looking after this plant makes me very proud,' Palm House Supervisor Will Spoelstra says. 'I see it as a symbol of the incredible history of the Palm House and Kew in general.

‘It still amazes me how long it has been here and how much the world has changed in this time.

'Hopefully it will live a lot longer yet, as I do not want to be known as “the Palm House Supervisor who killed the oldest pot plant in the world”.’

Illustration of Encephalartos altensteinii cone from 1891
Illustration of Encephalartos altensteinii cone from 1891 © RBG Kew

Conservation concentration

The species is classed as Vulnerable (VU) in the wild as a result of land clearance, according to IUCN Red List criteria.

However, it is quite common in its native South Africa, found near the coast in habitat ranging from open shrubland on steep rocky slopes to closed evergreen forests in valleys.

This species is listed on Appendix I of CITES, which permits trade only under exceptional circumstances. Tighter regulation helps protect wild populations.

We are monitoring the Eastern Cape giant cycad here at Kew as part of the Sampled Red List Index for Plants, which aims to produce conservation assessments for a representative sample of the world's plant species.

This information will lead to a better understanding of extinction risk and help focus conservation efforts where they are needed most.

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