RHS conference tackles water challenges in British gardens

Chelsea showpieces will focus on drought resistant plants and cost of living crisis

• Amit Roy
• 16 May, 2024

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By: Amit Roy

WATER conservation at homes and gardens and tackling the cost of living crisis were key themes at the RHS spring conference in London last week, when speakers discussed adapting to the UK’s wetter winters and drier summers.

At a day-long seminar, the Royal Horticultural Society also unveiled its plans for this year’s Chelsea and Hampton Court Palace flower shows from May 21 – 25 and July 2 – 7, respectively.

There were three sessions – money saving gardening, living the green dream and fashion and flowers – but the underlying message was about the need to make the best use of water. Several speakers stressed how gardening has to adapt and use more recycled water.

The day when people can pop out into their back garden and help themselves to a couple of ripe Alphonso mangoes hasn’t quite arrived, but attendees at Lindley Hall, the RHS headquarters in Vincent Square near Victoria, London, heard about drought resistant plants.

The RHS said: “Gardens showcasing clever rainwater management feature heavily at Chelsea this year, including ‘the water aid garden’, which includes a rainwater harvesting pavilion designed to slow its flow, collecting and storing it for irrigation of the garden and filtering it for use as drinking water.

“In ‘the national autistic society garden’, rainwater is channelled away from the main terrace via a ‘waterfall roof’ into a mossy dell which acts as a swale during periods of high rainfall, holding rainwater until it can drain away into the subsoil.

“Rain is also channelled into areas planted with species that can cope with wet conditions.”

There will also be a “water saving garden” at Chelsea.

RHS head of sustainability, Malcolm Anderson, said: “Over time, we will shift away from blue water sources.”

This point was also emphasised by senior water scientist at the RHS, Dr Nicholas Cryer, who said: “The greenest approach to watering your garden is to minimise its use entirely – through clever planting and good soil care – with rainwater harvesting the next best thing.

“But, with summers predicted to become hotter and drier and the need to remedy a growing water deficit, we need to be more creative in how we maintain our green spaces.

“The estimated 60 litres of greywater produced per person within our homes each day can be recycled in our gardens.”

The RHS offered some helpful tips: “Greywater can be used in the short term on ornamentals, but not edible crops. To minimise bacterial growth, greywater from sinks and baths should be stored for no more than 24 hours. Greywater should be applied by watering can as pollutants in the water can clog irrigation systems.”

Garden designer and journalist, James Alexander-Sinclair, who chaired one session, said: “It’s estimated that by 2028, we will have a bill for flooding as a nation of £27 billion.”

The landscape designer, Mark Gregory, told the RHS spring conference: “For every one degree (Centigrade) temperature rise, there is 70 per cent more water in the air.”

According to the RHS: “Greywater will be a go-to source of water for the garden by 2035”.

In fact, the government is targeting a 20 per cent reduction in household and business water use by 2038. It is “also looking at how water can be practically recycled from sinks, baths and washing”.

People will be encouraged not to use mains water in their gardens. The RHS said: “Fundamental to all rain gardens is healthy, deeply aerated soil which readily absorbs water, and then balances storage and deep drainage of that water. The microbes found in healthy soils improve the filtering capacity of soils by digesting organic matter from any greywater applied to it – such as detergents, skin and sweat, and enhancing soil structure.”

Digging the garden is not always a good idea, according to the RHS.

It said: “Your soil is your largest water storage reservoir. Improve it by adding organic mulch and minimising soil disturbance to improve structure and its ability to hold water. Healthy soil needs plants that cover and protect the soil and that have healthy root systems to improve its aeration and stabilisation.”

The RHS spring conference also heard how gardeners can save money.

Sheila Das, the garden manager at RHS Wisley, used the expression “chop and drop” to explain how people can make their own compost – by dropping chopped plants and leaves into a corner where they can decompose and become home-made compost.

At Hampton Court, there will be a “money-saving garden”, designed by Anya Lautenbach, who has written a bestselling book on how this can be achieved.

She told the conference: “As the nation is facing a high cost of living crisis, we would like to show that an amazing, breathtaking and beautiful garden doesn’t have to cost the earth or break the bank. We are using plants that are very easy to grow in British gardens. We are going to repurpose and recycle and reuse lots of materials.

“From a mature lavender plant, I can take cuttings in spring to get about 100 new plants. And don’t forget that lavender needs to be pruned anyway each year, so why not turn your waste into plants by pruning them and then growing those cuttings. And if you don’t have a garden, but want to grow more lavenders on your windowsills or containers, the same principle applies – prune them and then grow the cuttings to create new plants.”

Her spring pruning technique for hydrangeas means she can get up to 50 new plants a year. By cutting and dividing a mature hosta, people can get 10 new plants, she said.

It is also suggested that people save and swap seeds with neighbours and also change the way they harvest vegetables plants. “If you are taking leafy greens, just take the leaves that you need from the outside of the plant. They will actually continue for weeks or months. So you can get huge amounts of food from a single sowing. Spring onions are another good example. Slice it up, but leave the root base in the soil and it will regrow. You can get three regrowths off one spring onion.”

RHS director general, Clare Matterson, said: “We see every day how gardening and growing plants can provide much needed respite for people facing some of the toughest challenges and how it can bring joy in hard times. This makes us really want gardening to feel, and be, accessible and available to all. We want to share how gardening and growing plants at home doesn’t need to cost a fortune.”

The RHS aims to get children interested in gardening from the earliest age. This year they will pick the winner of the “RHS Children’s Choice Award”. Other highlights announced last week included a “Chelsea Repurposed Garden, created almost entirely out of repurposed materials”.

Tom Massey’s Islamic inspired fountain and concrete benches from his 2018 The Lemon Tree Trust Garden will provide a focal point and places to rest within the garden.

The recycling will continue with drought-tolerant species, including grasses and local wildflowers, all planted in crushed concrete and sand salvaged from demolished buildings.

Mention was also made of the watering system at a Roman villa that is looked after in Somerset by Newt, one of the main sponsors at Chelsea.

All gardens at Chelsea “have to live on in some form after the show”. Last year’s RHS/Eastern Eye “garden of unity”, designed by Manoj Malde, is now looked after by children at the Sacred Heart RC Primary School in Battersea in London.