Why Cultivated Plants Matter in an Urban Environment

A subject close to our hearts at the Horticultural Taxonomy department of the Royal Horticultural Society is the vastness of the UK cultivated flora – in fact, the latest RHS Plant Finder 2018 lists over 76,000 plants grown in the UK. Stroll through any village, town or city and it is clear that the botanical life of our urban places is dominated by cultivated plants. However, cultivated plants appear only rarely in Floras, the scientific work that catalogues the plant life of a given area. Recording introduced plants is essential if the ecosystems of our towns and cities are to be fully understood.

London street trees providing welcome shade for pedestrians on a sunny day. © Yvette Harvey.

Why Does this Matter?

There is increasing evidence that plants grown for ornament serve more than just an aesthetic function. The flexibility of fauna in adapting to available vegetation has been documented in a 30-year study of a suburban domestic garden (Owen, 2010). The four-year RHS experiment known as Plants for Bugs found that to encourage pollinating insects in gardens the best strategy is to plant a mixture of native and exotic flowering plants (Salisbury et al., 2015). There is also a greater understanding that the human environment can be managed by an informed use of cultivated plants. Examples include the value of street trees and green walls in mitigating heat island effect and the role of green spaces in reducing water runoff.

Pollinators visiting an ornamental flower bed. © Yvette Harvey.

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