Heatwave encourages banana plant to fruit for the first time in Cambridge

Experts say the UK’s climate is too inhospitable for the plants to flourish in the open air, but gardeners at Clare College expect to produce a crop of bananas within the next few weeks.

This summer’s heatwave appears to be the main reason for the plant’s fruiting even though it has not been kept under glass. At the moment it is so content that it is putting on a huge leaf every week and has two whorls of bananas.

“Our banana plants have never produced fruit before, and this has taken us by surprise,” said Stephen Elstub, Head Gardener at Clare College.

“A child noticed the large coconut-like flower last month and we have been giving it plenty of nutrients ever since to encourage the fruit to develop”.

Because banana plants can turn black due to frost, they are normally brought in over the winter. Last winter, however, the Clare gardeners left the plants out and this could further explain why they are now flourishing. “Leaving their roots undisturbed may also have helped them produce fruit,” Mr Elstub said.

The species is the ‘Japanese’ banana (Musa Basjoo), which was introduced to England in 1881 and soon became a feature in Cornish estate gardens. The plants will grow between six and ten feet high and usually flower in their fifth year.

The bananas should double in size within the next few weeks to about 12cm long and although they are not an edible variety, the gardeners are nevertheless keen to try them when ripe.

Two separate plants are needed for cross-pollination of the male and female flowers and wasps seem to be pollinating the Clare College bananas.

The Gardens are open from 10.45am to 4.30pm daily.

Clare is not the only Cambridge garden which is witnessing unusual events thanks to the warm weather. At the Cambridge University Botanic Garden, a Mexican sotol plant (Dasylirion serratifolium) is enjoying the heat so much that it has produced a flower spike that has outgrown its greenhouse.

“It has flowered here previously, but we’ve never needed to remove a pane of glass from the greenhouse before,” said Rob Brett, Glasshouse Supervisor at the Garden.

The sotol has been resident at the Garden for about 40 years and last flowered in 2001. The plant is now ten feet tall, including the seven foot flower spike. Due to renovations there is no public access to the greenhouse, but the plant can be seen from the outside as the spike makes its way through the roof.

The Cambridge University Botanic Garden is open from 10am to 6pm from April to September.

Source: University of Cambridge