Choosing native plants for a wildlife pond

Why native plants earn their place in a wildlife pond

A pond is only as good as the plants around it. Native species have evolved alongside our insects, amphibians and birds, so they offer the right nectar at the right time, the right leaves for caterpillars to chew, and the right seed heads for finches in autumn. A border of exotic marginals may look striking, but much of it will be ignored by the creatures you are trying to attract.

There is a practical side too. British natives are adapted to our rainfall, our winter cold and our sometimes unreliable summers. Once established, they need far less fussing than greenhouse-raised imports. Plant them well and they will settle in for years.

Getting to know the zones of a pond

Before you buy anything, look at your pond as a series of bands. Each has its own water depth and each suits a different group of plants. Planting by zone is the single most useful thing you can do.

• Bog and damp margin: the soil just above the waterline, always moist but rarely submerged.
• Shallow margin: 0–15cm of water, where most flowering marginals live.
• Deeper margin: 15–40cm, home to taller species such as flowering rush.
• Open water: floating-leaved plants and submerged oxygenators.

If your pond has a butyl or fibreglass liner, stand marginal plants in baskets on a shelf so you can control their spread. On a clay-lined or natural pond, many of these will naturalise happily in the mud.

Reliable natives for the margins

Start with a handful of dependable flowering species and let them knit together.

• Marsh marigold (Caltha palustris): the first big splash of gold in March and April, and a magnet for early bees. Happy in boggy soil or in a few centimetres of water.
• Water forget-me-not (Myosotis scorpioides): soft blue flowers from May to September. Newts lay eggs on the leaves, so it earns its keep twice over.
• Purple loosestrife (Lythrum salicaria): tall, upright and covered in bees and butterflies through midsummer. It can seed freely, so give it room or plant the sterile cultivar.
• Water mint (Mentha aquatica): fragrant, quick to spread and loved by hoverflies. Keep it in a basket if you want it contained.
• Flowering rush (Butomus umbellatus): pink umbels on stiff stems in late summer, for the deeper shelf.

Oxygenators and floating plants

Submerged plants do the quiet work of keeping water clear. They compete with algae for nutrients and give tadpoles somewhere to hide.

• Hornwort (Ceratophyllum demersum): floats free without roots, so no planting at all. Superb for small ponds and for shade in summer.
• Water starwort (Callitriche species): a native oxygenator that also carpets the surface, sheltering froglets.
• White water lily (Nymphaea alba): too vigorous for a small pond, but wonderful in a large one. For a modest pool, use a smaller native such as Nymphaea alba var. minor. Leaves shade the water and discourage algae.

Add one or two floating plants, but never introduce species such as water hyacinth or floating pennywort. They are non-native, grow explosively and are illegal to plant in the wild in the UK.

Planting, establishment and the first season

Plant between late spring and early autumn, when the water is warm and roots can move. Use baskets lined with hessian and filled with a low-nutrient aquatic compost — ordinary garden soil or multipurpose compost will leach nutrients and feed algae instead of your plants.

Set marginals so the crown sits just above the water surface, then top the compost with a layer of gravel to stop fish and birds rummaging. Give each basket a slow-release aquatic feed tablet in its first year, but hold back afterwards; overfeeding a pond is the quickest route to green soup.

Expect a wobbly first season. New plants sulk, blanketweed appears, and it all looks thin. Resist the urge to intervene. By the second summer the marginals will have closed ranks and the water will have found its own balance.

Caring for the planting year on year

Wildlife ponds are best left a little untidy, but a light hand at the right time keeps everything healthy.

• Late summer: thin out oxygenators by hand if they fill more than half the water volume.
• Early autumn: cut back excessive growth in baskets, but leave seed heads standing for the birds.
• Late winter: tidy the margins before frogs and newts return to spawn. Never clear a pond in spring.
• Always: leave any weed on the pond edge for a day so creatures can crawl back in.

Divide congested marginals every three or four years, in spring, and replant the healthiest sections. This is also the moment to remove any non-natives you have inherited from a previous owner — a job worth doing carefully, since some, such as New Zealand pygmyweed, must be disposed of responsibly and never composted near water.

Do that much and your pond will reward you: damselflies on the flowering rush, bees on the marigold, and a soft blue haze of forget-me-not at the water's edge from May onwards.