Eleanor Hartley
Why a wildlife pond is worth the effort
Even a modest pond—say two metres by three—can transform a garden into a haven. Frogs and toads arrive first, followed by newts, dragonflies, damselflies, pond skaters and water boatmen. These creatures need still, clean water, plenty of cover and a reliable supply of insects. Unlike a formal koi pond, a wildlife pond is happiest when it looks a little untidy. Your job is not to control it, but to gently steer it. The good news is that repairing and maintaining a pond takes only a few hours each season, and most of that is pleasant pottering with a net and a pair of gloves.
Assessing and repairing the pond structure
Before you clear a single leaf, walk around the pond and look for problems. A leaking liner or cracked clay base will never support wildlife. Check the water level in dry weather; if it drops more than a few centimetres a week without evaporation, you likely have a leak. Small punctures in butyl or EPDM liners can be patched with a proprietary repair kit, but work on a dry, mild day. If the pond is old and silted to the brim, do not empty it all at once. That would kill frogs, newts and countless invertebrates. Instead, remove silt in stages, leaving a third of the old material behind.
Edges matter as much as the water. A pond with steep, bare sides is a trap for hedgehogs and froglets. Create at least one shallow beach using stones, gravel or a piece of turf folded back into the water. Add a log or a gentle ramp so anything that falls in can climb out. If you have a natural spring feeding the pond, respect it: do not dam or divert it, and avoid digging near ancient wellheads or spring lines, which can be fragile and historically significant.
Clearing debris without evicting residents
Autumn leaves are the main enemy of clear water, but they are also food and shelter for many tiny creatures. The trick is timing and technique. Use a soft pond net rather than a rake, and skim leaves from the surface every few days in October and November. Leave the netted debris on the pond edge for 24 hours so any trapped larvae, beetles or newts can crawl back. Never leave a pile of rotting leaves in the water over winter; it will strip oxygen and release nutrients that feed algae.
- Do not dredge in spring or summer. Frog spawn, tadpoles and dragonfly nymphs are at their most vulnerable. Late autumn is the kindest time for major clearing.
- Leave some silt. A shallow layer at the bottom supports bloodworms, snails and overwintering insects.
- Cut back dead marginal plants in autumn, but leave the stems of reeds and irises standing over winter for insects to shelter in.
Planting native species for shelter and oxygen
Native plants are the backbone of a healthy pond. They oxygenate the water, shade out algae, and provide egg-laying sites for dragonflies and damselflies. Aim for a mix of submerged, floating and marginal species. Plant in baskets of hessian or plain aquatic compost—never use ordinary garden soil, which is too rich and will cloud the water. Avoid invasive non-natives such as floating pennywort, parrot’s feather and water fern; they can smother a pond in a single season.
- Submerged oxygenators: hornwort, water milfoil and curled pondweed.
- Floating plants: white water lily and frogbit. Keep them to a third of the surface so light can reach below.
- Marginal plants: marsh marigold, water forget-me-not, purple loosestrife and lesser spearwort.
- Edging plants: lady’s smock and ragged robin, which attract insects to the pond edge.
Keeping chemicals away from the water
This is the single most important rule. A wildlife pond and chemical treatments do not mix. Never use pesticides, herbicides, slug pellets or artificial fertilisers anywhere near the water. Even a small drift of spray can wipe out amphibians and the insects they feed on. If you have a lawn, leave a buffer strip of rough grass at least two metres wide around the pond. Use hand-pulling, mulching and barriers instead of weedkiller on paths and patios. When topping up the pond, use rainwater from a butt rather than tap water, which contains chlorine and chloramine. If you must use tap water in an emergency, add it slowly and only in small amounts, and never use a chemical clarifier or algaecide. Barley straw, a bundle of oxygenating plants and a little patience will usually sort out green water without any potions.
Seasonal maintenance for a thriving pond
Once the pond is repaired and planted, maintenance is mostly gentle observation. In spring, check for frog spawn and remove any blanket weed by twirling it around a stick. In summer, top up with rainwater during dry spells and keep the surface clear of duckweed. In autumn, net leaves and cut back excessive growth. In winter, float a ball or a bunch of twigs on the surface to prevent ice sealing the pond; never smash the ice, as the shock waves can kill fish and amphibians. If the pond freezes for more than a few days, melt a hole by placing a hot pan on the surface—gently. With a little care, your pond will reward you with frog chorus, darting dragonflies and a corner of the garden that feels truly wild.
