Invasives Blog

Plant hunters introduced many of the UK’s most damaging invasive species as botanical status symbols in the Victorian era.

Initially, the impact of plant hunting for sought-after specimens, such as camellia and rhododendrons, was largely unknown. However, without natural predators from their home range, these plants grew uncontrollably in British gardens and spread into the wild.

Rhododendron ponticum growing in English woodland. Image: Getty Images

How and why did plant hunting come about?

The introduction of various plants to Britain began in Roman times, but modern plant hunting really took hold in the 18th and 19th centuries.

In the 18th century French missionaries returned from China with descriptions and specimens of plants they found. This sparked a competitive race among nursery owners and botanical gardens in England who sent plant hunters overseas to get the most desired specimens.

Plant hunters famously risked life and limb to get their hands on the most exotic of plants. They faced the threat of shipwreck, piracy, disease and even imprisonment.

Which well-known invasive species were introduced by plant hunters?

Some of the species introduced as ornamental garden plants by the Victorians include Japanese knotweed, Himalayan balsam, water primrose, American skunk cabbage and rhododendron. Japanese Knotweed (Fallopia japonica) is one of the most destructive of these – it spreads rapidly, outcompetes native species and erodes riverbanks. In fact, it is so problematic that in the UK it is a criminal offence to cause or allow the plant to spread in the wild.

Rhododendron (Rhododendron ponticum) is an ornamental shrub introduced by the Victorians for its spring flowers. Poisonous to livestock, it can also carry the tree disease Phytophthora ramorum, which has killed thousands of larch, beech and oak trees in the UK.

Japanese knotweed. Image: andys465, Getty Images Signature

What has the environmental impact of plant hunting been?

Plant hunting has had a negative impact on biodiversity and native species around the world. Around 2,000 non-native plant and animal species have been introduced into the UK. Whilst most non-native species are harmless, around 10-15% have become invasive and have a negative impact in some way.

Many of the more harmful non-native plants started out as ornamental garden plants. Without any native predators, these plants grow uncontrollably, out-competing native species and disrupting local ecosystems.

Plant hunting has also had an impact on the habitats of host countries where over-collecting and damage to neighbouring plants have caused habitat loss and destruction.

Does plant hunting continue today?

Plant collecting today is guided by worldwide conservation legislation and licensing. This aims to create fair and equitable trading and compensation to host countries for plants, plant products and plant knowledge.

Himalayan balsam. Image: OlyaSolodenko from Getty Images

Invasive species expertise

CABI has worked on invasive species – one of the five leading drivers of global environmental change – for over 100 years. We provide robust data on how invasives impact on human well-being and the environment. Plus, we develop practical ways of tackling the biggest threats.

Find out more about our work with invasive species.

Further information about plant hunting: Kew Gardens website

CABI’s Invasive Species Compendium is an open-access reference tool. It provides detailed information identification, prevention and management of invasive species around the world.

Visit the Invasive Species Compendium

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