How to Design a Garden to Cope with Flood and Drought Conditions
Discover ways to avoid flood damage to your garden while also helping it to survive hot, dry spells
With a combination of too much rain at times and not enough at others, gardeners are facing a real challenge when it comes to designing an outdoor space that can cope with our changing climate.
Here, three experts discuss how you can take steps to prevent both flood damage and drought conditions, creating a comfortable and safe space for you to enjoy, whatever the weather.
Professional advice from: Dr Nicholas Cryer, Senior Water Scientist at the RHS; Claudia de Yong of Claudia de Yong Garden Design; Melanie Hick of Melanie Hick Garden Design;
Here, three experts discuss how you can take steps to prevent both flood damage and drought conditions, creating a comfortable and safe space for you to enjoy, whatever the weather.
Professional advice from: Dr Nicholas Cryer, Senior Water Scientist at the RHS; Claudia de Yong of Claudia de Yong Garden Design; Melanie Hick of Melanie Hick Garden Design;
What are the key considerations for coping with drought conditions in our
gardens?
1. Harvest every drop of rainwater
Ensuring you’ve stored supplies of rainwater to get you through dry periods is the first step for coping with long, hot spells, followed by using that water as close to its source as possible.
“For example, rainwater can be captured on a roof and used to support a green roof, before flowing into a landscape and to a storage area (pond or bog),” Nicholas says.
Using rainwater can also help gardens to become ‘water-neutral’ – the term used to describe a garden that reduces and offsets its water footprint.
“Rainwater is a neutral source, but mains water or water taken from a river is not, because it has been removed from the environment,” Nicholas explains. To become water neutral, “gardeners can choose to capture rainwater and store it in either tanks or in the soil, so it’s available when needed”.
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1. Harvest every drop of rainwater
Ensuring you’ve stored supplies of rainwater to get you through dry periods is the first step for coping with long, hot spells, followed by using that water as close to its source as possible.
“For example, rainwater can be captured on a roof and used to support a green roof, before flowing into a landscape and to a storage area (pond or bog),” Nicholas says.
Using rainwater can also help gardens to become ‘water-neutral’ – the term used to describe a garden that reduces and offsets its water footprint.
“Rainwater is a neutral source, but mains water or water taken from a river is not, because it has been removed from the environment,” Nicholas explains. To become water neutral, “gardeners can choose to capture rainwater and store it in either tanks or in the soil, so it’s available when needed”.
2. Water strategically
Avoiding overwatering is another thing to keep in mind. “Many gardeners overwater,” Nicholas says. “Best practice is to check the soil below the surface before watering [the surface is often dry while just beneath is still moist]. Water infrequently and be guided by the plant’s appearance.”
“Water early morning or early evening to avoid evaporation during the heat of the day, therefore ensuring plants receive the right amount of water at the right time,” says Claudia, who also recommends mulching plants well “to retain soil moisture and reduce evaporation”.
Avoiding overwatering is another thing to keep in mind. “Many gardeners overwater,” Nicholas says. “Best practice is to check the soil below the surface before watering [the surface is often dry while just beneath is still moist]. Water infrequently and be guided by the plant’s appearance.”
“Water early morning or early evening to avoid evaporation during the heat of the day, therefore ensuring plants receive the right amount of water at the right time,” says Claudia, who also recommends mulching plants well “to retain soil moisture and reduce evaporation”.
3. Choose plants carefully
“Choosing drought-tolerant plants, especially native varieties that can cope with the rising temperatures, will help your garden cope with drought conditions,” Claudia says.
“Plant choice is very important,” Nicholas agrees. The RHS has lists of plants well suited to dry conditions and plants suitable for both wet and dry soils.
“The microclimate can be very important, with factors such as shade from a higher canopy providing much-needed protection for short plants,” Nicholas continues. “This can be practiced at many different levels, as seen in woodland gardens.”
Looking to countries that are used to dealing with extreme temperatures can also offer guidance when choosing plants. “Consider drought-tolerant plants such as those from the more arid regions of Australia,” Melanie suggests. “Eucalyptus ‘Mount Bogong’ is my favourite small tree for these conditions.”
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“Choosing drought-tolerant plants, especially native varieties that can cope with the rising temperatures, will help your garden cope with drought conditions,” Claudia says.
“Plant choice is very important,” Nicholas agrees. The RHS has lists of plants well suited to dry conditions and plants suitable for both wet and dry soils.
“The microclimate can be very important, with factors such as shade from a higher canopy providing much-needed protection for short plants,” Nicholas continues. “This can be practiced at many different levels, as seen in woodland gardens.”
Looking to countries that are used to dealing with extreme temperatures can also offer guidance when choosing plants. “Consider drought-tolerant plants such as those from the more arid regions of Australia,” Melanie suggests. “Eucalyptus ‘Mount Bogong’ is my favourite small tree for these conditions.”
Need some garden advice? Easily find and hire garden designers on Houzz.
4. Choose naturalistic planting and keep grass long
“Naturalistic planting often makes use of deeply rooted perennial species that are resilient to water shortages,” says Nicholas, who names the Piet Oudolf borders recently planted at RHS Garden Wisley as a good example.
Allowing your grass to grow a little longer can help to make it more drought-resilient, too. “If you have grass, allow it to stay long, as long grass has deeper roots, and accept that it may becomes brown in drought times,” Nicholas says. “Long grass will bounce back with rainfall, whereas short grass is more likely to die.”
“Naturalistic planting often makes use of deeply rooted perennial species that are resilient to water shortages,” says Nicholas, who names the Piet Oudolf borders recently planted at RHS Garden Wisley as a good example.
Allowing your grass to grow a little longer can help to make it more drought-resilient, too. “If you have grass, allow it to stay long, as long grass has deeper roots, and accept that it may becomes brown in drought times,” Nicholas says. “Long grass will bounce back with rainfall, whereas short grass is more likely to die.”
5. Improve your soil
Nourishing your soil is a key part of regenerative gardening and can help your plot to store water and withstand hot, dry spells more comfortably, too.
“Improving soil structure with organic matter enhances its water-holding capacity and promotes healthy root growth,” Claudia says.
“The soil in your garden can hold a lot of water,” Nicholas says. “Each square metre of soil could hold 100 litres of water within reach of the plant rooting zone (assume 50cm, but some plants can root much deeper).
“No-dig methods, where the soil is only minimally disturbed for planting or harvest and is dressed with a layer of mulch, builds soil structure and function, allowing more water to be held,” he says.
More: What is Regenerative Gardening?
Nourishing your soil is a key part of regenerative gardening and can help your plot to store water and withstand hot, dry spells more comfortably, too.
“Improving soil structure with organic matter enhances its water-holding capacity and promotes healthy root growth,” Claudia says.
“The soil in your garden can hold a lot of water,” Nicholas says. “Each square metre of soil could hold 100 litres of water within reach of the plant rooting zone (assume 50cm, but some plants can root much deeper).
“No-dig methods, where the soil is only minimally disturbed for planting or harvest and is dressed with a layer of mulch, builds soil structure and function, allowing more water to be held,” he says.
More: What is Regenerative Gardening?
What are the key considerations for managing flood risk in our gardens?
1. Understand your soil type
Having a detailed knowledge of your garden and how it handles water is the first step to understanding and managing flood risk. “[For example,] clay soils retain water [while] sandy soils drain more quickly,” Claudia says, so this will impact the flood patterns in your space.
“The first point is to understand the topology of your site and the wider water catchment area,” Nicholas says. This means understanding “the water flow to the garden and from the garden, the topology that may cause water to pool at predictable locations, and the amount and timing of rainfall.
“This will allow you to understand if the site will flood regularly, maybe with the season, and how long the flooding may last,” he continues. “If it’s only a transient event, then no special intervention is needed. Transient flooding can be a good thing, allowing [you to include different kinds of plants] and building greater biodiversity.”
1. Understand your soil type
Having a detailed knowledge of your garden and how it handles water is the first step to understanding and managing flood risk. “[For example,] clay soils retain water [while] sandy soils drain more quickly,” Claudia says, so this will impact the flood patterns in your space.
“The first point is to understand the topology of your site and the wider water catchment area,” Nicholas says. This means understanding “the water flow to the garden and from the garden, the topology that may cause water to pool at predictable locations, and the amount and timing of rainfall.
“This will allow you to understand if the site will flood regularly, maybe with the season, and how long the flooding may last,” he continues. “If it’s only a transient event, then no special intervention is needed. Transient flooding can be a good thing, allowing [you to include different kinds of plants] and building greater biodiversity.”
2. Invest in permeable surfaces
To allow water to drain into the soil and avoid excess run-off from hard surfaces, choose permeable materials for any hard landscaped areas.
“We can remove a lot of hard paving to make way for permeable surfaces,” Melanie says. “In many instances, cars don’t need to stand on concrete. You can easily strip out a paved-over front garden and replace it with planting and gravel.
“There are many subterranean urban drainage solution products that we install beneath the gravel and garden that you’d never know were there, but help water to drain away,” she says.
To allow water to drain into the soil and avoid excess run-off from hard surfaces, choose permeable materials for any hard landscaped areas.
“We can remove a lot of hard paving to make way for permeable surfaces,” Melanie says. “In many instances, cars don’t need to stand on concrete. You can easily strip out a paved-over front garden and replace it with planting and gravel.
“There are many subterranean urban drainage solution products that we install beneath the gravel and garden that you’d never know were there, but help water to drain away,” she says.
3. Slow the flow
“We can also design gardens to deliberately intercept storm flows and hold that water for use,” Nicholas says. “Increasingly, we’re seeing rain gardens where excess water from rainfall or flood is diverted to an area of the garden where the water can infiltrate the soil. This reduces flooding further downstream or prevents excess water entering combined sewers and leading to sewer overflow.
“Slowing the flow links environmental stewardship with good gardening,” he adds. “Additionally, by filling the soil with water, this builds a store for drier times.”
“We can also design gardens to deliberately intercept storm flows and hold that water for use,” Nicholas says. “Increasingly, we’re seeing rain gardens where excess water from rainfall or flood is diverted to an area of the garden where the water can infiltrate the soil. This reduces flooding further downstream or prevents excess water entering combined sewers and leading to sewer overflow.
“Slowing the flow links environmental stewardship with good gardening,” he adds. “Additionally, by filling the soil with water, this builds a store for drier times.”
4. Embrace the beauty and cooling aspects of water in your outdoor space
Thinking about flooding can be stressful, but, correctly managed, water flow through a garden needn’t be a negative.
“Seeing water move through a landscape and celebrating the value of water is an important aspect of [a garden designed to manage water flow].” Nicholas says.
“What I want to see in the wider garden design community is more examples of gardens using water to provide environmental services,” he continues. “This could be the feeling of wellbeing from the garden display, but also cooling of our environment by evaporation or shading.”
Nicholas suggests selecting plants not only for “structural shade and aesthetic appeal”, but also “for the evaporative cooling potential to provide a comfortable space for enjoying the garden”.
Take a tour of the flood-resilient garden seen here.
Thinking about flooding can be stressful, but, correctly managed, water flow through a garden needn’t be a negative.
“Seeing water move through a landscape and celebrating the value of water is an important aspect of [a garden designed to manage water flow].” Nicholas says.
“What I want to see in the wider garden design community is more examples of gardens using water to provide environmental services,” he continues. “This could be the feeling of wellbeing from the garden display, but also cooling of our environment by evaporation or shading.”
Nicholas suggests selecting plants not only for “structural shade and aesthetic appeal”, but also “for the evaporative cooling potential to provide a comfortable space for enjoying the garden”.
Take a tour of the flood-resilient garden seen here.
How can we future-proof our gardens?
Our climate is changing rapidly and designers are having to adapt and learn as temperatures rise across the globe. This means new ideas and solutions are emerging all the time. Making use of greywater is one such solution that could become more widely adopted.
“In the future, the competition for access to water will become more intense” Nicholas says. “For many locations, rainwater harvesting will not be sufficient to support gardens through the whole of dry periods and the use of mains water will be restricted. Greywater, produced from domestic activities such as washing and cooking, will become a more important and mainstream component of water supply for gardens.
“The advantages are that greywater is produced from normal household activities each day and should be used as soon as enough has been collected; there’s no need for large storage tanks,” he continues. “The RHS is supporting work to develop greywater systems incorporating plants for retrofit to domestic situations.”
According to Melanie, the use of greywater is an established practice in countries such as Australia, which are habitually in water restriction, although it is subject to regulations concerning its safe use and storage. More research may be needed before it’s considered a practical option in the UK, but watch this space.
Tell us…
What steps have you taken to manage water in your garden? Share your thoughts and tips in the Comments.
Our climate is changing rapidly and designers are having to adapt and learn as temperatures rise across the globe. This means new ideas and solutions are emerging all the time. Making use of greywater is one such solution that could become more widely adopted.
“In the future, the competition for access to water will become more intense” Nicholas says. “For many locations, rainwater harvesting will not be sufficient to support gardens through the whole of dry periods and the use of mains water will be restricted. Greywater, produced from domestic activities such as washing and cooking, will become a more important and mainstream component of water supply for gardens.
“The advantages are that greywater is produced from normal household activities each day and should be used as soon as enough has been collected; there’s no need for large storage tanks,” he continues. “The RHS is supporting work to develop greywater systems incorporating plants for retrofit to domestic situations.”
According to Melanie, the use of greywater is an established practice in countries such as Australia, which are habitually in water restriction, although it is subject to regulations concerning its safe use and storage. More research may be needed before it’s considered a practical option in the UK, but watch this space.
Tell us…
What steps have you taken to manage water in your garden? Share your thoughts and tips in the Comments.
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All our experts agree this has become a central consideration.
“Water management is crucial for resilient gardens; the future of garden design is water-friendly,” Melanie Hick says. “We’re experiencing long, wet winters and springs, and dry summers. We can prepare our gardens to survive by being smart with the plants we choose and how we use water.”
“Environmental stewardship has become a core principle in garden design today,” Claudia de Yong agrees. “With climate change, the need for water conservation requires effective management, ensuring healthy gardens as well as a good ecological balance.”
“Drought is an increasingly frequent event and is having an impact on garden design,” Dr Nicholas Cryer says. “There’s a growing interest and application of ecological principles to garden design that is driving an increased interest in water management.”