Wildlife garden

Collecting rainwater and letting it soak into your garden

Keep rainwater in your garden with a water butt or tank for watering, and by letting the rest soak in through a swale or rain garden: a shallow, planted hollow where the water from the roof runs to.

Updated on 10 October 2026

What to do

Connect a water butt to the downpipe with a diverter that sends the overflow back, and use the water for watering.
Where you can, disconnect a downpipe and lead the water to a spot in the garden where it can soak away.
Dig a hollow there 20–30 cm deep, with gently sloping sides, at least a few metres from the house.
Plant the hollow with plants that tolerate both wet feet and drought, such as purple loosestrife, meadowsweet, hemp agrimony, yellow loosestrife and water avens.
After a heavy downpour, check that the water drains away within a day or two; on heavy clay, make the hollow larger or shallower.

Why it helps

In our region an average of some 800 litres of rain falls on each square metre of roof every year. If it goes into the drains, it is lost to your garden and overloads the sewers in heavy downpours.
Water that soaks into the ground tops up the groundwater and keeps your garden moist for longer in dry summers.

Which plants?

Purple loosestrife Lythrum salicaria perennial · flowers June–September Native
Meadowsweet Filipendula ulmaria perennial · flowers June–August Native
Hemp agrimony Eupatorium cannabinum perennial · flowers July–September NativePoisonous
Yellow loosestrife Lysimachia vulgaris perennial · flowers June–August Native
Yellow flag Iris pseudacorus water or marginal plant · flowers May–June NativePoisonous
Water avens Geum rivale perennial · flowers April–June Native
Devil's-bit scabious Succisa pratensis perennial · flowers August–October Native

When?

March–October.

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Take up the challenge

Put out a water dish (June–August)
Put out a shallow dish of water with a stone in it, for birds, hedgehogs and insects. Refresh it every few days.

Go to Challenges and badges

Did you know? Rainwater is soft and contains no lime or chlorine: houseplants and plants for acid soil, such as rhododendron and blueberry, prefer it.