Start with Sun and Shelter

Butterflies are cold-blooded and need to raise their body temperature to around 30°C before they can fly properly. That single fact shapes everything about where a butterfly border should go. A strip along a south- or west-facing wall, fence or hedge is ideal: it catches the sun for most of the day, and the boundary behind it blocks the wind. If your only available spot is exposed, plant a low, dense hedge of lavender, rosemary or beech a metre or two in front of the border to break the gusts. Even a few large shrubs can make the difference between a border that butterflies visit and one they simply fly over.

Soil matters less than warmth, but drainage does. Most nectar plants dislike sitting in cold, waterlogged clay over winter. Fork in some well-rotted compost and a handful of grit before planting, and you will give everything a far better start. Leave a few flat stones or a patch of bare, sun-warmed earth among the plants as well. Brimstones and commas will settle there with their wings spread, soaking up heat between feeding bouts.

Fill the Border with Nectar

Adult butterflies take nectar, and they are fussier than you might expect about how they take it. Flat, open, daisy-like flowers with a landing platform are far easier to use than deep trumpets or tightly double blooms. Single flowers are always better than doubles, which often hide the nectar altogether. Aim for drifts of three to five plants of the same kind rather than one of everything: butterflies spot a block of colour from a distance and will work along it methodically.

• Buddleia — the classic, but plant it at the back and cut it hard in March to keep it manageable
• Lavender, catmint and marjoram — long-flowering, drought-tolerant and superb for peacocks and small tortoiseshells
• Verbena bonariensis — airy stems that let you see through to the plants behind
• Sedum spectabile — the ice plant, a magnet for commas and red admirals in late summer
• Knapweed, field scabious, teasel and ox-eye daisy — British natives that fit beautifully into a relaxed border
• Michaelmas daisies and asters — invaluable for topping up energy reserves before hibernation

Don't Forget the Caterpillars

Nectar feeds the adults, but caterpillars need something entirely different, and most species will only use one or two specific food plants. A border full of buddleia and lavender will bring in butterflies from elsewhere, yet it will not produce the next generation. If you want brimstones, commas and peacocks breeding in your garden, you need to feed their young as well.

• Stinging nettle — the essential food plant for peacock, small tortoiseshell, red admiral and comma caterpillars
• Alder buckthorn and purging buckthorn — the only plants brimstone caterpillars will eat
• Cuckooflower and garlic mustard — for the orange-tip, which is increasingly scarce in gardens
• Holly, ivy and dogwood — food for holly blue caterpillars
• Native grasses — meadow grasses feed speckled wood, meadow brown and gatekeeper larvae

If a nettle patch feels too untidy, sink a large pot of nettles into the ground at the sunny end of the border and cut it back to about 30 centimetres in midsummer to encourage fresh, tender growth. Butterflies lay on the young shoots, so a light trim every few weeks keeps the patch productive.

Plan for a Long Season

Butterflies are on the wing from March to November, so a border that peaks for three weeks in July will only ever be half useful. Stagger the flowering by choosing plants from each of these groups.

• Early spring: aubrieta, wallflower, forget-me-not and cuckooflower
• Early summer: catmint, allium, salvia and ox-eye daisy
• High summer: buddleia, lavender, marjoram, knapweed, scabious and verbena
• Late summer and autumn: sedum, aster, rudbeckia and helenium
• Late autumn: ivy flowers, which are a lifeline for red admirals before hibernation

Easy Maintenance That Helps

A butterfly border is a low-effort border, provided you resist the urge to tidy too enthusiastically. Leave seedheads standing through the winter — they feed goldfinches, shelter overwintering insects and look wonderful in frost. Delay cutting back perennials until late March or early April, once the worst of the cold has passed. Allow a little leaf litter to gather at the base of the plants, and build a small log pile in a quiet corner for hibernating brimstones and commas.

Avoid insecticides completely, including sprays aimed at aphids, because they will kill caterpillars along with the pests. Tolerate some chewed leaves: ragged foliage on nettles, holly or buckthorn is a sign that your border is working exactly as it should.

What You Might See

With sun, shelter, nectar and larval food in place, a well-planted border can support a genuinely surprising range of species. Brimstones arrive early, sometimes in February, patrolling the length of the border before settling on a wallflower. Commas and peacocks bask on warm stones in midsummer, and small tortoiseshells often return to the same patch of nettles year after year. Add a shallow dish of water with a few pebbles for drinking, keep the border sheltered and untidy at the edges, and watch it fill up.