Kew and the Royal Parks plan for drier summers as water supplies stay tight

The planting in London’s parks and gardens is being rethought as hotter, drier summers squeeze the capital’s water supply. Thames Water, the supplier for most of the city, said its levels are still short of where they were before this summer’s record heat, and that a long spell of rain is needed before hosepipe restrictions can be relaxed.

Southern England has never recorded a drier month than this July. At Kew Gardens, not a drop of measurable rain was logged.

Drought-tolerant planting at Kew Gardens

Kew is already changing what it grows and how it waters, choosing species that get by on less and irrigating with water it has captured itself. One choice is agave montana, which grows wild on Mexican mountainsides, survives on very little water and is a relative of the plant distilled into tequila.

The restrictions cover hosepipes and sprinklers in parks and public gardens, although Kew has an exemption so that its National Plant Collections are protected. Thomas Freeth, head of collection management at the gardens, said the job now is to think harder about where the water comes from. A “glorified water butt”, as he described it, was installed recently and kept three of Kew’s thirstiest glasshouses going to the end of July.

What hotter summers mean for London’s trees

The Royal Parks is preparing for the same conditions, which could cut short the lives of established trees. Darren Share, its director of parks, said trees that would be expected to have another 150 odd years of growth might now have between 50 and 70, and that it is something the organisation needs to keep watching.

A recent Greater London Authority report found that, if nothing changes, more than 72% of the trees in London’s current public realm will struggle in future climate conditions. Trees help the city cope with heat by providing shade and some protection from extreme weather.

Thames Water said it would carry on monitoring rainfall and water levels, with restrictions kept under review. The Environment Agency classes the South East as “seriously water stressed”, and the company said that doing nothing would leave it one billion litres a day short by 2050. It pointed to new sources, including the White Horse Reservoir and the Teddington drought-resilience scheme, alongside work to cut leaks. Two-thirds of the people it recently polled said they were worried about a consistent supply, while fewer than a third thought supplies would always be plentiful.