Why these insects are worth designing for

Dragonflies and damselflies are among the most rewarding wildlife you can bring to a British garden. They are fast, colourful and genuinely predatory, hawking midges and mosquitoes out of the air above a pond on a warm July afternoon. They also tell you something useful: if dragonflies are breeding, your pond has clean water, healthy plant growth and a functioning food web. A garden pond without them is often a pond that is too shaded, too tidy or too full of goldfish.

The good news is that they are not fussy about postal codes. Even a modest pond of two or three square metres will draw them in if it offers the right combination of sunlight, still water, emergent stems and somewhere to sit. Get those four things right and you will often see your first damselflies within a season, with dragonflies following as the pond matures.

Designing a pond that suits them

Sunlight is the single most important factor. Dragonfly nymphs need warm water to develop, and adults need warmth to fly and hunt. Aim for at least six hours of direct sun on the water surface, ideally more, which usually means siting the pond away from north-facing walls and mature trees.

Depth matters too. A profile with a shallow shelf of 10–20 cm, a middle zone around 40 cm and a deeper section of 60–80 cm in the centre gives you the best of everything: warm shallows for nymphs, a refuge from frost and drought, and plenty of planting niches.

Then there is the question of fish. If your priority is dragonflies and amphibians, leave the fish out. Even a few goldfish will hoover up nymphs and tadpoles with alarming efficiency. Sticklebacks do the same. Keep the pond fish-free and you will see far more insect life.

• Siting: full sun, sheltered from strong wind, away from overhanging branches.
• Size: bigger is better, but 2 × 3 metres works well; an irregular outline adds edge habitat.
• Edges: gently sloping sides, plus a few stones or a log ramp so hedgehogs and frogs can climb out.
• Water: rainwater or tap water left to stand for a few days; avoid run-off from fertilised beds.

Emergent plants do the heavy lifting

Emergent plants are the backbone of any dragonfly pond. Nymphs climb up them to leave the water for their final moult, adults rest on them between flights, and they provide cover for the small invertebrates that feed everything else. Aim for around a third to a half of the water surface planted, with dense clumps rather than neat spacing.

• Yellow flag iris (Iris pseudacorus) — bold, tall, excellent vertical stems for emergence.
• Water mint (Mentha aquatica) — nectar-rich flowers, caterpillar food, and happy in shallow water.
• Purple loosestrife (Lythrum salicaria) — a magnet for insects in late summer.
• Bog bean (Menyanthes trifoliata) — fringed flowers in spring and floating leaves for cover.
• Marsh marigold (Caltha palustris) — early flowers and good marginal cover.
• Soft rush, sedges and sweet grass — slender stems that damselflies love to cling to.
• Submerged oxygenators such as hornwort and water starwort — essential for nymphs to hunt among.

Top up with a few water lilies in the deeper zone, which shade the water in summer and give emerging insects somewhere to rest. Avoid invasive non-natives such as floating pennywort, water fern and New Zealand pigmyweed, which are illegal to plant in the wild and a nightmare to remove once established.

Perches, basking spots and bare ground

Adult dragonflies are sunbathers. They need warm, exposed surfaces to raise their body temperature before they can fly at full speed, and they are surprisingly loyal to a favourite perch. Provide several and watch the same individual return to it again and again.

• Leave dead flower stems and seed heads standing over winter — they double as spring perches.
• Push a few bamboo canes at an angle into the pond margin, angled towards the sun.
• Sink a couple of large flat stones so they protrude just above the waterline.
• Keep a patch of bare, sun-warmed earth or gravel beside the pond.
• Allow a nearby shrub to grow slightly loose — darters and hawkers use the outer twigs.

What the nymphs need to complete the cycle

Breeding, rather than just visiting, is the real prize. Females lay eggs by dipping the tip of the abdomen into water or by inserting eggs into plant tissue, depending on species. The nymphs that hatch are aquatic, voracious and slow-growing, spending anywhere from a few months to three years underwater before they emerge.

They need submerged and floating vegetation to hide in, leaf litter and detritus to hunt through, and clean, oxygen-rich water. A pond with nothing but open water will not support them. Crucially, they also need a way out: vertical stems, iris leaves or rush culms that reach at least 30 cm above the surface, so the nymph can climb clear of the water and split its skin for the final time. Leave a fringe of tall plants at the water's edge and you will regularly find the empty brown husks of emerged nymphs clinging to them on a June morning.

Managing the pond through the year

The best wetland gardens are gently untidy. Resist the urge to strip the pond in autumn, and never clear it all in one go — nymphs and larvae overwinter among stems and sediment. If you must thin plants, do it in late spring or early summer, in stages, and leave the cuttings on the bank for a day so anything that crawls out can return to the water.

Top up with rainwater rather than tap water where you can, never use insecticides or weedkillers near the pond, and let fallen leaves settle into the deeper section as food and cover. Within a year or two you should see azure and blue-tailed damselflies, common darters and possibly a broad-bodied chaser. A mature pond in a good location, surrounded by long grass and flowering plants, may attract emperors and southern hawkers too. Give it sun, stems and stillness, and they will find you.