Prairie Planting: An Oudolf-Style Border

Prairie planting turns a border into a slice of grassland. Ornamental grasses form the backbone, and late-flowering perennials rise through them in loose drifts. It moves in the breeze, looks good for most of the year, and needs only one proper cut.

The style is linked with the Dutch designer Piet Oudolf and the wider “New Perennial” movement. Here’s how to build one in a UK garden: what to plant, the soil it likes, how to lay it out and when to cut it. If you’re still choosing between styles, the guide to modern mixed border design with plant communities compares prairie planting with other naturalistic looks.

What is prairie planting, and why does it work?

Prairie planting copies the tallgrass prairies of North America. Grasses make a living background, called the matrix, and flowering perennials push up through it. The result holds its shape long after the petals drop.

It works because plants are chosen for their shape and seedheads, not just their flowers. A short list of plants is repeated across the bed, so it reads as calm rather than busy. Oudolf’s planting on the High Line in New York and at Hauser and Wirth Somerset made the look famous. In Britain, Nigel Dunnett and James Hitchmough of the University of Sheffield helped design the meadows at the London 2012 Olympic Park.

Repeat a few plants in loose drifts and the border reads as calm and natural, rather than a jumble.

Which grasses make the best prairie backbone?

Start with two or three grasses and repeat them right through the bed. Use enough of them to form a continuous background, or the scheme turns back into an ordinary flower border.

• Calamagrostis x acutiflora ‘Karl Foerster’: stiff, upright stems that flower in early summer and stand all winter. The easiest backbone to start with.
• Molinia caerulea subsp. arundinacea ‘Transparent’: tall, see-through stems that give the grassland feel without blocking the view.
• Deschampsia cespitosa: soft, airy clouds of flower in summer. The deschampsia growing guide covers the best varieties.
• Sporobolus heterolepis and Panicum virgatum: good in warmer, sunnier gardens, with fine autumn colour.

Low sun shining through calamagrostis and molinia is one of the best things about a prairie border.

Which perennials grow well in a prairie border?

Choose flowers with strong shapes that still look good once they’ve gone over. Mix upright spires, daisies and flat heads so there’s contrast against all the grass.

Echinacea can be short-lived on heavy soil, so give it the best-drained spot. The guides to growing echinacea and veronicastrum’s tall spires cover each plant in more detail.

Close planting lets grasses and echinacea prop each other up, so you don’t need stakes.

What soil and site does prairie planting need?

Full sun and lean, free-draining soil. Aim for at least six hours of sun a day. Most prairie plants come from open grassland on poor soil, and that’s what keeps their stems short and sturdy.

Warning: Don’t add manure or fertiliser to a prairie bed. Fed plants grow tall and soft, flop in the first summer storm and are more likely to rot over winter.

Heavy clay is the main problem in UK gardens. Cold, wet soil rots crowns in winter. Fork plenty of grit through the top spade’s depth before you plant, or build a slightly raised bed. On very wet ground, lean on plants that cope with heavier soil, such as persicaria, veronicastrum and asters. The guide to improving clay soil has more ways to open it up.

On heavy clay, grit worked in before planting helps the crowns get through a wet winter.

How to plant a prairie border step by step

Plant in spring, from April to May, so roots settle before winter. This matters most on clay and for echinacea.

1. Clear all perennial weeds first. Couch grass and bindweed are almost impossible to remove once the bed is planted.
2. Improve drainage on heavy soil with grit. Don’t add compost or manure.
3. Lay the grasses out first, in loose, irregular groups that repeat across the bed.
4. Add the perennials in drifts of three to seven, threading them between the grasses. Repeat each one at least twice.
5. Plant closely, roughly 5 to 9 plants per square metre depending on size. Small 9cm pots are fine and establish quickly.
6. Water well, then mulch with grit or gravel rather than rich compost.

Keep on top of weeds and water in dry spells for the first two summers. After that, the plants knit together and shade out most weeds.

Prairie border calendar: what to do each month

A prairie border needs little work, but the timing matters.

Hold your nerve in autumn: cut in October and you lose months of structure. The guide to the best plants for winter seedheads suggests more plants that look good all winter.

Frosted stems and seedheads are part of the design. Leaving them standing isn’t neglect.

How to cut back a prairie border

Prairie borders get one cut a year, in late February or early March, just before new shoots appear. Cut grasses and perennials together, down to about 5-10cm.

Waiting gives you the winter show and leaves seed for birds. Shears are fine for a small bed. For a big one, a hedge trimmer saves a lot of time. Rake off the cuttings and compost them, or chop them small and leave a thin layer as mulch. Don’t feed afterwards.

Is prairie planting good for wildlife?

Yes, it feeds wildlife in two seasons. In summer, open flowers like echinacea, monarda, sedum and persicaria bring in bees, hoverflies and butterflies.

In winter, seedheads of grasses, echinacea and rudbeckia feed goldfinches and other seed-eating birds. Hollow stems also shelter overwintering insects. That’s another good reason to leave the cut until late winter.

Open, daisy-like flowers such as echinacea are easy for bumblebees to feed from.

Common mistakes with prairie planting

• Soil that’s too rich. This is the main reason prairie borders fail. Fed plants grow soft and flop by August. Never feed the bed.
• Planting too far apart. Wide gaps let weeds in and leave plants to flop on their own. Plant closely so they support each other.
• Too many different plants. One of everything looks busy. Use a short list and repeat it.
• Too few grasses. Skimp on grasses and it turns back into an ordinary flower border.
• Cutting back in autumn. You lose the winter structure and bird food, and leave bare soil for months.
• Ignoring wet clay. Crowns rot in waterlogged soil. Add grit, raise the bed, or choose plants that cope.

Once established, prairie borders are one of the easiest ways to fill a sunny bed. For more easy-care ideas, see the guide to creating a low-maintenance garden, or browse more garden design ideas.

Now you know how a prairie border is built, read the guide to ornamental grasses for UK gardens to choose the grasses for yours.

Frequently asked questions

What is prairie planting in a garden?

It’s grasses and late-flowering perennials mixed together in loose, natural-looking drifts. The style copies North American grassland. Grasses form the background and flowers such as echinacea rise through them. It’s often linked with the Dutch designer Piet Oudolf, and shape and seedheads matter as much as flower colour.

How many grasses should a prairie border have?

Use plenty, enough to form a continuous background. Too few and it looks like an ordinary flower border with a grass or two added. Pick two or three grasses and repeat them right across the bed, then thread the flowers through them.

Does prairie planting work on clay soil in the UK?

Yes, if you improve the drainage first. Most prairie plants rot in cold, wet clay over winter. Work plenty of grit into the top spade’s depth, plant in spring rather than autumn, and choose plants that cope with heavier soil, such as persicaria, veronicastrum and asters.

When do you cut back a prairie border?

Cut everything down once, in late February or early March. Leave the stems standing through winter for structure, frost and bird food. Cut just before new growth starts, taking the whole bed down to about 5-10cm. Rake off the cuttings and compost them.

Do prairie plants need staking?

Not usually, if the soil is lean and the planting is close. Neighbouring plants and grasses hold each other up. Plants on rich, well-fed soil grow soft and tall, and those are the ones that flop and need canes.

What are the best grasses for a UK prairie border?

Calamagrostis ‘Karl Foerster’, molinia and deschampsia are reliable choices. ‘Karl Foerster’ gives an early upright shape, tall molinia adds a see-through veil, and deschampsia makes a soft summer haze. All three stand well into winter.

Is prairie planting low maintenance?

Yes, once it’s established. There’s one cut a year, no feeding and no deadheading. The first two seasons need regular weeding and watering in dry spells while the plants knit together. After that the dense planting shades out most weeds.