Why a soggy corner is an opportunity

Most of us have one: the patch at the bottom of the garden that squelches underfoot from November to March, grows more moss than grass, and has defeated every attempt at a tidy lawn. Instead of fighting it with land drains and bags of sand, work with it. Wet ground is one of the scarcest habitats in the British countryside — the vast majority of our lowland wet meadows have vanished since the mid-twentieth century — and a patch of it, even three or four square metres, can be extraordinarily rich in life.

Wetland wildflowers are also generous. They flower hard, they seed freely, and they thrive on neglect. You do not need a pond, a stream or a field. A boggy strip behind the shed, the shady run-off from a downpipe, or a permanently damp border is enough to start.

Reading the wet: work out what your ground actually does

Before ordering any seed, spend a winter watching the site. Wet ground comes in several flavours, and each suits a different mix of plants.

• Seasonally waterlogged — standing water in winter, dry and cracked by July. The most common garden situation, and the easiest to plant.
• Permanently damp — firm underfoot but never truly dry, with lively moss and rushes. Dig a spade-depth hole in February; if water seeps in and stays, you are in this category.
• Genuinely boggy — springs, seepage lines and the edges of ditches, where the soil is saturated all year. Plant the thirstiest species here.
• Pond margin — the strip just above the waterline that floods after heavy rain.

Also note how much sun the spot receives. A damp, sunny corner is the jackpot; a damp, shaded one limits you to a narrower but still worthwhile palette.

Native plants that thrive in damp British ground

Buy seed of British native provenance where you can, and avoid generalised "wildflower" mixes that contain cornfield annuals or non-native species. For a small wet patch, a mix drawn from this list will perform well:

• Ragged robin — frothy pink flowers from May, happiest in the wettest ground and generous with seed.
• Meadowsweet — tall, creamy and almond-scented; a magnet for hoverflies and small beetles.
• Cuckooflower (lady's smock) — pale lilac in spring, and the larval food plant of the orange-tip butterfly.
• Marsh marigold — bold golden cups in March and April, ideal at a pond edge.
• Water mint — low, spreading and wonderfully aromatic, loved by bees.
• Purple loosestrife — tall magenta spires from July; superb for long-tongued bees.
• Devil's-bit scabious — rounded mauve pincushions late in the season, when little else is in flower.
• Yellow flag iris — architectural foliage and yellow blooms for permanently wet spots.
• Yellow rattle — a semi-parasite that weakens grasses and lets flowers through. Sow it in autumn; it needs winter cold to germinate.

Add a light background of native grasses such as tufted hair grass, crested dog's-tail or greater pond sedge rather than ryegrass, which is far too vigorous.

Sowing and planting a small wet meadow

Timing matters more than technique. Late August to mid-October is ideal: the soil is warm, rain is plentiful, and seedlings establish before winter. Early spring is a workable second choice.

Start by cutting the existing growth as short as you can and raking off the cuttings. On rich, damp ground this matters enormously — wetland soil is usually nutrient-heavy, and fertility encourages coarse grasses at the expense of flowers. Do not add compost, manure or fertiliser. If the site is thick with nettles or rank grass, strip the top few centimetres of turf entirely and stack it upside down to rot down into loam for next year.

Rake the surface to a crumbly tilth, sow at roughly 1–2 grams per square metre for a flower-rich mix, then tread or roll the seed in so it makes firm contact with the soil. Keep off it for a few weeks. Plug plants are the surer route in a very small space: plant five to nine per square metre in autumn or spring, water them in, and keep the surrounding grass cut short while they settle.

Miniature bogs in tubs and containers

If your only wet space is a patio, make one. A half-barrel, a builder's bucket or a lined wooden crate with no drainage holes will hold a bog garden perfectly well.

• Fill with a peat-free, loam-based compost mixed with about a quarter grit or sharp sand for weight and stability.
• Drill no holes. Keep the compost permanently moist, with an inch or two of water sitting above it in winter only.
• Plant marsh marigold, water mint, ragged robin, lesser spearwort or a compact sedge. One or two taller species, such as purple loosestrife, give height.
• Top up with rainwater from a butt rather than tap water, which is alkaline and nutrient-rich. In a dry summer, containers dry out fast — check them every couple of days.

Cutting, care and the wildlife you'll attract

In the first year, cut the patch every six to eight weeks to about 7cm to knock back annual weeds and let the flowers tiller. From the second year, switch to a single annual cut in late August or early September, once the seed has dropped. Cut by hand or with a strimmer, leave the cuttings lying for a day or two so seed falls, then rake them off. Removing the material is what keeps fertility low and the flowers competitive. Never cut when the ground is waterlogged, or you will poach it into a mud bath.

Leave the stems standing over winter. Seed heads feed goldfinches, tussocks shelter frogs, toads and newts, and the hollow stems of plants like teasel and sedge make overwintering quarters for insects. Come the following June you can expect bumblebees, solitary bees, hoverflies, soldier beetles and, if you are lucky, damselflies hunting along the damp foliage. A soggy corner, planted well and then largely left alone, becomes the busiest part of the garden.