Why a Pond Is the Single Best Thing You Can Add

Of all the improvements you can make to a British garden, a pond punches far above its weight. Even a modest one — say two metres by one and a half — will draw in wildlife that simply cannot use the rest of your plot. Frogs and toads need water to breed, smooth newts and palmate newts need it even more, and dragonflies and damselflies will patrol it from May to September. Hedgehogs, bats and thirsty birds all visit for a drink.

The joy of a pond is that it works on its own terms. Once it has settled, it needs far less attention than a border of bedding plants. What matters is getting the basics right at the start: the shape, the slope, the position and what you plant in and around it.

Choosing the Spot and Getting the Shape Right

Position is everything. Aim for a spot that gets sun for at least half the day — frogs and dragonfly larvae both develop faster in warmer water — but avoid the deepest shade of a large tree, where you will spend every autumn fishing out leaves. A pond beneath a sycamore or willow is a losing battle.

Do not site it in the lowest, boggiest corner unless you genuinely want a marsh. And keep it away from where you might use slug pellets; frogs eat slugs, and poisoned frogs are a common and avoidable loss.

The most important design feature is the edge. Vertical sides may look neat, but they are a death trap for hedgehogs, and they give amphibians nothing to climb. Instead:

• Build one gently sloping side, no steeper than about 30 degrees, so frogs, newts and even a thirsty cat can walk in and out.
• Include a shallow shelf 20–30 cm deep for marginal plants, and one deeper area of 60–90 cm where creatures can overwinter below the ice.
• Add a shallow "beach" of pebbles or gravel at one end — a favourite basking spot for dragonflies.
• If your pond must have steep sides, lay a piece of rough timber or a gentle ramp of stones from the water to the bank as an escape route.

Filling It and Letting It Settle

Rainwater is ideal, so if you can, fill from a water butt. Tap water contains nutrients and traces of chlorine that feed algae, so if you have to use it, let the pond stand for a week or two before planting. A new pond will almost certainly turn green in its first spring. This is normal and temporary — do not panic and do not empty it. Once plants establish and grazing creatures arrive, the water clears on its own.

Never introduce fish to a wildlife pond. Even a few goldfish will hoover up frogspawn and dragonfly larvae within weeks and turn the water cloudy. If you have inherited a pond with fish, a separate small container pond elsewhere in the garden will still bring in amphibians and insects.

Planting Safely and Sensibly

Native plants are the priority, because our insects evolved alongside them. Aim for a mix of submerged oxygenators, floating plants and marginals.

• Oxygenators: hornwort, water milfoil and curled pondweed — good for shelter and spawning.
• Floaters: native water lily and frogbit provide shade and landing pads for insects. Avoid the invasive water hyacinth, which is illegal to release into the wild.
• Marginals: marsh marigold, water forget-me-not, ragged robin, yellow flag iris and purple loosestrife. Keep yellow flag in a basket, as it spreads vigorously.
• Bankside cover: leave a rough patch of long grass, logs and leaf litter nearby for hiding places and hibernation.

Use baskets of hessian or mesh for anything vigorous, and never plant invasive non-natives such as New Zealand pygmyweed or floating pennywort — these are banned from sale in the UK and can escape into local waterways.

Maintenance Through the Year

Less is more. Tidy ponds support less life than slightly scruffy ones, so resist the urge to over-manage.

• Spring: thin oxygenators if they fill more than half the water.
• Summer: top up in dry spells with rainwater, and leave the edges unmown so amphibians have cover.
• Autumn: net out fallen leaves, but leave a few in the bottom as food for larvae.
• Winter: float a ball or piece of timber to keep a hole in the ice. Never smash the ice — the shock can kill frogs resting below. Always leave any silt you clear on the side for a day so creatures can crawl back.

Give it a full year before judging. By the second spring you will hear a chorus of frogs, watch newts surfacing for air, and see dragonflies hawking over the water on a warm June afternoon. Few garden features repay patience so richly.