Rain garden planting: smart combinations for water buffer gardens

Why a rain garden?

Climate change brings more extreme downpours. At the same time, groundwater levels drop during dry spells. A rain garden — also called a swale or bioretention area — captures rainfall, lets it infiltrate slowly and keeps your garden green in summer. It is gardening that genuinely makes a difference.

With GardenWorld you can see how a rain garden would look in your space. Upload your photo and experiment with shapes and planting.

Combination 1: The classic rain garden

At the lowest point: Iris pseudacorus (yellow flag iris, 100 cm) and Lythrum salicaria (purple loosestrife, 120 cm). On the slope: Molinia caerulea 'Edith Dudszus' (purple moor grass, 80 cm) and Eupatorium maculatum 'Atropurpureum' (Joe Pye weed, 150 cm).

At the drier edge: Deschampsia cespitosa (tufted hair grass, 80 cm) and Geranium 'Rozanne' (cranesbill, 40 cm, blue flowers). This combination handles both waterlogged soil and weeks of drought.

Combination 2: Native and pollinator-friendly

Filipendula ulmaria (meadowsweet, 120 cm, creamy white) in the wet zone, paired with Angelica sylvestris (wild angelica, 150 cm) and Caltha palustris (marsh marigold, 30 cm, bright yellow).

On the transition: Succisa pratensis (devil's bit scabious, 60 cm) and Sanguisorba officinalis (great burnet, 100 cm, dark red bobbles). A paradise for bees, butterflies and hoverflies.

Combination 3: Modern with ornamental grasses

Panicum virgatum 'Shenandoah' (switchgrass, 120 cm, red autumn tones) as the main grass. Between them Veronicastrum virginicum 'Fascination' (culver's root, 140 cm, pale purple) and Persicaria amplexicaulis 'Firetail' (bistort, 120 cm, deep red).

In the wetter areas: Carex pendula (pendulous sedge, 100 cm) and Rodgersia pinnata 'Superba' (rodgersia, 80 cm, pink plumes). Structurally rich and spectacular from June to November.

Combination 4: Compact for small gardens

For a modest swale of two by three metres: Juncus effusus 'Spiralis' (corkscrew rush, 40 cm) in the centre, surrounded by Luzula nivea (snow rush, 30 cm, white tufts) and Astilbe chinensis 'Pumila' (dwarf astilbe, 25 cm, lilac-pink).

At the edge Ajuga reptans 'Atropurpurea' (bugle, 10 cm, dark purple foliage) as ground cover. Compact, colourful and functional.

Construction and maintenance

Dig a shallow bowl (20-30 cm deep) with gentle slopes. Direct rainwater from your roof or terrace via a channel or pipe into the swale. The base should not be waterproof — the water needs to percolate slowly.

Mulch with wood chips in the first year. After two years the plants form a closed canopy and the rain garden is virtually maintenance free. Cut back old stems in early spring.

Your rain garden

Every garden has space for water storage. Even a sunken planting bed along the drive makes a difference. Discover at gardenworld.app how a rain garden could make your garden more beautiful and climate resilient.