Flooding can cause immense damage to homes and gardens, yet this devastating, costly and disruptive weather extreme is becoming all too familiar across much of the UK – with milder, wetter winters now a regular occurrence due to climate change.
With autumn upon us, September and October offer a perfect window of opportunity to take steps that will mitigate the flood risk. So, if you have been thinking “How do I stop my garden from flooding?” just follow our 10-point action plan to help bolster your garden’s flood defences before winter sets in.
1. Tackle Flood-Prone Lawns
Lawns on heavy soils such as clay, or ground that has become compacted due to heavy wear over summer, is prone to flooding – but early-autumn TLC can work wonders. Rake grass vigorously using a spring-tine rake or use a powered lawn scarifier to pull out dead material, then aerate by spiking the lawn with a garden fork. This process opens up the surface and allows air and water to penetrate down to the rootzone. If grass looks sparse after scarifying, overseed using a fast-germinating lawn seed during September and early October. It’ll help to thicken your grass and prevent muddy patches. Established lawns benefit from an autumn feed that’ll strengthen the roots and help turf to withstand soggy conditions.
2. Install Permeable Paving
We’re a nation of garden-lovers, but we adore our cars too, and that’s why more and more front gardens are being paved for off-street parking, a big contributor to flash flooding, as hard standings cannot absorb stormwater. The Royal Horticultural Society claims that three times as many front gardens are now paved over compared to 10 years ago, with 4.5 million front gardens (that’s one in four) buried under concrete, while five million front gardens contain no plants at all! The cheapest permeable alternative for parking is gravel, but it can be a magnet for cat fouling, so consider laying grass reinforcement: a heavy-duty matrix system that allows cars to be parked on grass without the area turning into a mudbath. Interlocking permeable paving, which has the appearance of traditional block paving but contains gaps to allow water to drain away, is a clever solution for parking in front gardens.
3. Plant Moisture Lovers
Successful gardening is all about growing the right plants in the right place. Few plants will tolerate long periods in waterlogged ground as a lack of oxygen causes roots to rot, but a select few will relish the opportunity to thrive in permanently moist soil. The Siberian dogwood (Cornus alba ‘Sibirica’) is a top choice for damp areas, grown for its vivid crimson stems in winter while hydrangeas (especially Hydrangea paniculata) also adore moist soil. Hostas will thank you for planting in damp shade (watch out for slugs!) and arum lilies (Zantedeschia aethiopica) will put on a spectacular show of funnel-shaped white flowers when grown in moist soil. Looking for a tree with spectacular autumn colour? The sweet gum (Liquidambar styraciflua) is tolerant of heavier, moisture-retentive soils.
4. Fit Drain Leaf Guards
Most of us don’t give a second thought to drains until they block, resulting in a costly nightmare to fix. Debris caused by fallen leaves is a common cause of obstructions in drains, yet many properties have no barrier that prevents leaves from clogging grates, resulting in flooding. Plastic drain leaf guards that sit on top of drains can be bought online for less than a fiver, allowing rain water to drain but preventing debris from entering the system.
5. Give Plant Pots A Health Check
Plants growing in containers year-round can become waterlogged and ‘drown’, so give plant pots a health check. Remove saucers from underneath containers that have been in place to trap water run-off during summer. Tip the pot on one side and use a pencil or dibber to unblock any obstructions from drainage holes. Next, raise plant pots up off the ground to help water to drain. Decking tiles or bricks are a cheap solution, or buy pot feet at garden centres.
6. Build Raised Garden Beds
Raised garden beds are the answer to gardeners’ prayers where heavy soil is prone to flooding. They are an excellent choice for growing flowers, fruit and vegetables that would otherwise perish in soggy soil and their ornamental appearance makes an attractive feature, while soil in raised beds warms-up quickly in spring. Even beds raised up a few inches above ground level will help to improve garden drainage. Ready-to-build raised bed kits are available, or construct frames out of wooden sleepers or decking timber and fill with quality topsoil.
7. Improve Soggy Soil
Heavy, flood-prone soil can be improved by digging in lots of organic matter (well-rotted garden compost or manure). When adding new plants, mixing grit into the base of planting holes will help with drainage, while planting shrubs on slightly raised mounds can help to protect roots from brief periods of waterlogging. Avoid walking on soil when it’s saturated or your boots will further compact the ground, making the situation worse.
8. Boost Butts and Tackle Gutters
Reducing the flood risk by harvesting rainwater builds up a resource to keep gardens irrigated next summer. Water butts can be linked to gutters on homes, sheds, greenhouses and garages. Slimline butts hold around 100 litres of water and fit into small gaps and alleyways, while bigger 250-litre containers are best where space allows. Connecting kits are a worthwhile investment for linking butts. Clearing gutters of fallen leaves is an essential autumn job that prevents gutters from overflowing during storms. This chore can be eliminated by installing a gutter brush, a long cylinder that looks like a chimney sweep’s brush and sits snugly in gutters, preventing leaves from accumulating and disintegrating. You can also attach a gutter cleaning kit to some of our electric and petrol leaf blowers and shredders which can help make the job easier!
9. Plant a Green Roof
Green roofs, a biodiversity-enhancing carpet of dwarf perennials, are taking root on the roofs of sheds and bin stores across the UK. As well as creating a home for insects and pollinators, these carpets of plants soak-up rainwater, helping to prevent run-off that contributes to flooding. Ensure that roofs are sturdy, then line with waterproof membrane and build a frame using pressure-treated timber before filling with specialist, lightweight, green roof compost. Sedum mats are a popular choice for planting a low-maintenance green roof, while sempervivums make a stunning addition with their eye-catching rosettes. Adding dwarf ornamental grasses creates a prairie-like appearance.
10. Dig a Soakaway
If you have an area of your garden that’s consistently boggy, the good news is that you can help to alleviate the problem by digging a soakaway. It’s no substitute for installing professional drainage, but can help excess water to filter down into the ground. The bad news is that you need to dig deep, at least one metre for it to be effective. Fill the hole with hardcore (large stones and pieces of broken brick) before replacing the topsoil.
Which of these options for flood-proofing would work in your garden? Let us know in the comments.
Marc Rosenberg bio
Marc Rosenberg is a freelance garden writer and editor. A former journalist with Amateur Gardening and Horticulture Week magazines, he holds seven Garden Media Guild Awards. Marc has written for publications including The Garden magazine, BBC Gardeners’ World and RHS online.