Attracting dragonflies to a garden pond

Why dragonflies are worth designing your pond around

Few garden moments beat the sight of a dragonfly patrolling your pond on a warm July afternoon. Those iridescent blues and bronzes are not just beautiful; they are a sign that your water feature is functioning as a proper habitat. Dragonflies and damselflies are among the most ancient of flying insects, and they are surprisingly fussy about where they breed. Give them what they need and they will arrive within a season or two, often from ponds several streets away.

The good news is that the requirements are straightforward. A pond with still water, a few tall stems to climb, and plenty of underwater life for the larvae to hunt will do the job. The bad news is that a few common features of ornamental ponds work against you. If you have goldfish, a fountain, or a bare, steep-sided liner, you may be waiting a long time.

Still water is non-negotiable

Dragonfly nymphs are ambush predators. They live underwater for between one and three years, depending on the species, lurking among leaves and debris before launching themselves at tadpoles, midge larvae and small worms. They cannot cope with fast-moving water, and they are easily disturbed by constant surface movement.

This is the single biggest reason garden ponds fail to attract them. A fountain or a pumped waterfall that churns the surface may look lovely, but it makes the water unsuitable for breeding. If you want dragonflies, consider:

• Running any pump on a timer, switching it off for long stretches of the day, or better still, overnight and through the warmest hours when females are egg-laying.
• Keeping a separate still section of the pond, screened by stones or planting, that never sees current.
• Avoiding airstones and spitters altogether in a wildlife-focused pond.
• Positioning any waterfall so the plunge pool is far from the shallow margins where egg-laying happens.

If your heart is set on moving water, that is fine. Just treat the still end as the priority and accept that breeding will happen there, not in the splash zone.

Build in a shallow shelf and a deep refuge

Dragonflies need two very different depths in the same pond. Around the edges, a shallow shelf of 10–20cm gives females somewhere to dip their tails and deposit eggs into submerged stems or moss. Without a shelf, they simply have nowhere to land and lay.

In the middle, aim for a depth of at least 60cm, and 75cm if you can manage it. This deeper zone stays cool and stable through summer and gives nymphs a refuge from predators during winter. A pond with only shallow water will overheat, turn green and dry out, which spells disaster for larvae that need two winters to mature.

If you are retrofitting an existing pond, a shallow shelf can be created with a stack of flat stones, a submerged crate of gravel, or a marginal planting basket positioned just below the surface. It does not need to be pretty. It needs to be stable and accessible.

Plant tall stems and emergent foliage

The moment a nymph is ready to transform, it climbs out of the water and grips a vertical stem. This is one of the most vulnerable stages of its life, and it needs a plant strong enough to hold its weight as it splits its skin and pumps blood into its wings.

Good choices for a UK pond include:

• Soft rush and hard rush, both excellent for climbing and hardy across the country.
• Purple loosestrife, tall and nectar-rich, which also draws in bees and butterflies.
• Flowering rush and water mint for lower, denser cover around the margins.
• Reedmace (bulrush) if you have space and can contain its spread in a basket.
• Irises such as Iris pseudacorus, whose sword-like leaves make ideal emergence sites.

Include a mix of heights and let some stems stand through winter rather than cutting everything back in autumn. Nymphs overwinter in the pond and will use the dying foliage as cover.

Be careful with fish

This is where many well-meaning pond owners come unstuck. Goldfish, koi and even sticklebacks will happily eat dragonfly eggs and young nymphs. A pond stocked with a dozen fish can effectively sterilise itself for dragonflies.

You do not have to empty your pond of fish entirely, but be realistic. A small number of goldfish in a large, densely planted pond with plenty of shallow margins may coexist with dragonflies. Heavy stocking, or a pond under 1,000 litres, almost certainly will not. If dragonflies matter more to you than fish, consider:

• Keeping the pond fish-free and letting natural colonisation do the work.
• If fish are present, only keeping a very light stocking density and plenty of hiding cover.
• Avoiding the introduction of fish into a wildlife pond after dragonflies have established.

Newts, on the other hand, are fine. They eat some larvae but will not wipe out a population, and they make a pond far richer for the trouble.

Care through the seasons

Once dragonflies have found you, the job is mostly about restraint. Leave your pond alone as much as possible between October and March. Resist the urge to clean the bottom out; the silty layer is full of nymphs and other invertebrates. Skim off leaves from the surface in autumn so they do not overwhelm the water, but do not dredge.

In spring, clear any excess blanketweed by hand rather than with chemicals. Dragonfly larvae are sensitive to treatments, and so are the midge and mayfly populations they feed on. Top up the pond with rainwater where you can, as tap water adds nutrients and can trigger algal blooms.

Come midsummer, watch for the exuviae, the empty husks left behind on stems after emergence. Finding one is the surest sign that your garden has become a breeding site rather than just a stopping point. A pond that supports dragonflies is a healthy pond in every respect, and the reward is a show of flying jewels from June to September.