Making a Wildlife Pond in a Country Garden

Siting the Pond: Sun, Shelter and a Little Untidiness

Nothing lifts a country garden quite like water. A pond brings dragonflies over the lawn and frogs into the vegetable beds, and once it settles it needs far less attention than a herbaceous border. The secret is to build it for wildlife from the first spadeful, rather than digging a hole and hoping for the best.

Start with position. Most pond creatures want warmth, so aim for four to six hours of sun a day, ideally with the water catching the morning light. Full midday sun will encourage blanketweed, while deep shade under an old yew or cedar will leave the water cold and lifeless. A spot with dappled afternoon shade is close to ideal.

Shelter matters too. A pond in a windswept corner will be churned about and the marginal plants will sulk. If your garden has a walled garden, a crumbling brick retaining wall or a mature hedge, use it. Leave a rough margin of long grass, log piles and leaf litter nearby. Frogs and newts spend most of the year out of the water, and they need somewhere damp and untidy to hide.

Shape, Depth and Gentle Slopes

A wildlife pond is not a formal pool. Irregular, curving outlines look right in a period garden and give more edge for the money. As a rough guide, a pond of two to three metres across will support a genuinely interesting range of creatures; anything much smaller tends to overheat in July.

Depth should vary. Dig a central area of 60–80cm, deep enough to stay unfrozen at the bottom in a hard winter, then work outwards in shelves and slopes.

• Shallow shelves at 20–30cm for marginal plants and basking insects.
• A sloping beach on one side, no steeper than about 1 in 5, so hedgehogs, frogs and thirsty birds can walk in and out safely.
• Rough, uneven edges rather than a neat stone rim, giving cover for young amphibians.

Before you do anything else, lay a rope or hosepipe on the ground and live with the shape for a week. It is far easier to adjust a hosepipe than a hole.

Lining and Filling

Butyl or EPDM liner is the practical choice for most gardens, laid over a fleece underlay on a bed of soft sand, with the edges tucked into a shallow trench and hidden under turf or gravel. Avoid building the pond directly beneath a large deciduous tree: falling leaves will rot down and feed the algae.

Fill from a water butt if you possibly can. Rainwater is soft, free of chlorine and far kinder to plants. If you must use mains water, let it stand for a week or so before planting, and add a bucketful of water from a healthy established pond if a neighbour has one — it seeds the microscopic life that makes the whole thing work. Do not add tap water conditioner and expect miracles; time is the real remedy.

Planting with Native Species

Native plants are the backbone of a wildlife pond. They shelter larvae, provide emergence stems for dragonflies and damselflies, and oxygenate the water without bullying everything else.

• Marginals: marsh marigold, water forget-me-not, flowering rush, water mint and purple loosestrife.
• Emergents: flag iris and lesser reedmace, kept in baskets so they do not take over.
• Oxygenators: hornwort, water starwort and curled pondweed, planted in a basket of hessian-topped loam in the deeper water.

Plant in ordinary garden soil topped with gravel, never in rich compost. Nutrients are the enemy of clear water. And do check before you buy: Australian swamp stonecrop, parrot's feather and floating pennywort are invasive non-natives and should never go near a garden pond.

The Case Against Fish

Here is the single most useful piece of advice in this article: if you want frogs, newts, beetles and dragonfly nymphs, do not put fish in your pond. Even a handful of goldfish or a few rudd will hoover up tadpoles and invertebrate larvae with grim efficiency, and they stir up sediment and add nutrients all day long.

Leave the water alone and the pond will stock itself. Frogs and newts will arrive within a season or two, often crossing a surprising distance of dry ground to find water. Pond skaters, water boatmen, diving beetles, damselflies and the occasional great diving beetle follow. Birds will drink and bathe on the shallow beach. What you lose in fish, you gain tenfold in interest.

Looking After It Through the Year

A wildlife pond should be gardened lightly. Cut back excess growth in autumn and leave the cuttings on the bank for a day or two so anything clinging to them can crawl back to the water. Clear fallen leaves with a net before they sink, but do not be fanatical — a little leaf litter is part of the ecosystem.

Never empty and scrub a pond in spring; that is when everything is spawning. If blanketweed becomes a nuisance, twirl it out with a stick in early summer and leave it beside the pond overnight to let the creatures escape. Resist chemicals entirely.

Above all, be patient. A new pond often looks a bit raw for a year, then suddenly, one warm May morning, it is alive with movement. That is the reward for digging it properly in the first place.