Why Winter Matters for Your Wildlife Pond

Winter can feel like a quiet time in the garden, but your pond is alive with subtle activity. Native aquatic and marginal plants are slowing down, yet they continue to provide vital cover for frogs, newts, dragonfly larvae and a host of invertebrates. The key is to resist the urge to tidy too much. A gentle approach now will protect the creatures tucked into silt and hollow stems, and it will set your wetland plants up for a strong spring. Here is how to care for them without disturbing the life that depends on them.

Cutting Back Dead Growth: What to Leave and What to Take

As herbaceous marginal plants die back, you might be tempted to cut everything to the ground. Please don't. Many native species, such as purple loosestrife, yellow flag iris and water mint, have hollow or pithy stems that make perfect winter bedrooms for insects. Ladybirds, small beetles and solitary bees may be sheltering inside. Seed heads, too, feed birds like goldfinches and reed buntings.

Instead, cut back only the dead, collapsing growth. Use sharp secateurs or snips, and leave stems at around 10–15 centimetres above the water level or the crown of the plant. This keeps hollow stems available while preventing the plant from smothering neighbouring species. Remove the cuttings from the pond edge—don't let them fall in and rot, as this adds nutrients and can encourage algae. If you find a stem packed with insects, simply leave that one standing.

• Leave: Seed heads of purple loosestrife, marsh woundwort and sedges; hollow stems of reeds and rushes; any stems with visible exit holes or insects.
• Cut: Soggy, collapsed leaves of yellow flag iris and marsh marigold; decaying foliage that is already turning to sludge.
• Angle cuts: Cut just above a leaf node or bud to prevent water pooling and rot.

Keeping Oxygenators Submerged and Healthy

Native oxygenating plants—hornwort, water starwort, rigid hornwort and common water-crowfoot—are the lungs of your pond. In winter, they grow slowly but still need to stay submerged. If any strands float to the surface, gently ease them back under with a stick or your hand. Don't be tempted to remove them all; even in cold water they provide cover for tadpoles, sticklebacks and diving beetles. However, if a mass of oxygenator has died and is breaking up, scoop out the worst of it to prevent deoxygenation. Leave the healthy green tips. In a small pond, you can simply sink a weighted bundle of hornwort to the bottom, where it will remain dormant but alive until spring.

Protecting Dormant Wildlife in Silt and Stems

The silt at the bottom of your pond is not just mud. It is a winter refuge for frogs, newts, dragonfly nymphs, damselfly larvae, water snails and countless microscopic creatures. They bury themselves deep, often below the frost line. This is why you should never dredge, vacuum or stir up the silt between late autumn and early spring. Even a gentle prod with a net can disturb them and expose them to cold or predators.

Similarly, hollow plant stems and seed heads above the water are used by overwintering insects. A stem of great reedmace or a clump of soft rush can hold dozens of small creatures. Leave them standing. If you must trim, do it in late February or early March, just as new growth begins. By then, most residents will have emerged. Also, avoid cutting back marginal plants below the waterline—submerged sections offer hiding places for newts and small fish.

Ice, Water Levels and Other Winter Jobs

When the pond freezes, do not smash the ice. The shockwaves can kill fish, frogs and insects, and the noise is distressing. Instead, place a pan of hot water on the surface to melt a hole. This allows toxic gases to escape and oxygen to enter. Remove the pan once a hole forms. Keep a hole open during long cold spells.

Check water levels after heavy rain or frost. If the level drops, top up with rainwater from a water butt, not tap water, which contains nutrients and chlorine. In winter, rainfall usually does the job, but a dry, cold snap can lower levels. Also, clear any fallen leaves from the pond surface—especially from non-native trees—but leave those from native species like alder or willow if they fall in small amounts. They provide food for invertebrates.

Looking Ahead: The Gentle Spring Tidy

Resist the urge to do a big clean-up now. The best time to divide overgrown marginal plants, thin out oxygenators and remove excess silt is late spring, once the water has warmed and wildlife is active. For now, your role is simply to observe and protect. Enjoy the frost patterns on the pond, the visiting birds and the knowledge that beneath the surface, a whole community is sleeping safely. Your native aquatic and marginal plants will reward this patience with vigorous growth and a thriving wildlife pond come April.