A white border does something no other colour scheme can: it keeps working after the sun goes down. As the light drains from a summer evening, reds and blues collapse into grey, but white flowers hold their brightness and seem to float in the dusk. Group them well and you can walk the garden at ten o'clock at night and still read the shape of it.

Why white flowers glow after sunset

White petals reflect almost the whole visible spectrum rather than absorbing part of it, so they make the most of whatever light is left. Human eyes also switch to rod-dominated vision in low light, which is far more sensitive to brightness than to colour. The result is that a white bloom appears to brighten relative to its surroundings as the evening draws in.

There is a bonus for wildlife too. Many moths navigate and feed at dusk, and pale flowers are easier for them to find. Plant a white garden and you are effectively laying a table for night-flying pollinators as well as pleasing yourself.

The backbone: roses, shasta daisies and gypsophila

Start with plants that give you bulk and repeat performance, then use smaller, airier things to stitch them together.

• White roses. Choose repeat-flowering shrub roses such as Rosa 'Iceberg' or the softer, more fragrant 'Desdemona'. They flower from June into autumn and their pale blooms catch the last of the light beautifully. Give them full sun, a rich mulch in spring and a feed in early summer.
• Shasta daisies. Leucanthemum x superbum is the classic, with crisp white rays around a gold eye. 'Snowcap' stays compact at around 40cm, which suits the front of a border or a large pot. Deadhead weekly and it will keep producing right through to September.
• Gypsophila. Gypsophila paniculata 'Bristol Fairy' throws up a cloud of tiny white flowers on wiry stems. It needs sharp drainage and a sunny spot, and it resents being moved, so plant it where it is to stay. The haze it creates softens the edges of heavier flowers and looks almost luminous at dusk.

Planting it well, in borders and pots

White schemes are unforgiving of gaps. Aim to plant in odd-numbered groups — three or five of the same variety — so each clump reads as a deliberate block rather than a stray dot. Space shrub roses about 90cm apart; they need the airflow to keep blackspot at bay.

Before planting, fork the bed over and work in two or three bucketfuls of well-rotted manure or garden compost per square metre. Roses and daisies are hungry plants and will reward you for it. Gypsophila prefers a leaner, limier soil, so add grit to its planting hole and a handful of lime if your soil is acidic.

For pots, use a loam-based compost such as John Innes No 2 rather than a lightweight multipurpose, which dries out far too fast in July. Put crocks in the base, plant the daisies and gypsophila together for a frothy, self-supporting display, and stand the pot where you will actually see it after dark — beside a bench, by a doorway, at the top of a path. Water daily in hot weather and feed fortnightly with a high-potash tomato feed once buds appear.

Night-scented plants to weave in

Colour is only half the story. The other half is scent, and the best of it arrives after sunset. Interplant a few of these among the whites:

• Nicotiana sylvestris — tall, architectural and heavily perfumed in the evening.
• Night-scented stock (Matthiola bicornis) — unremarkable by day, unforgettable at dusk. Sow direct in May.
• Evening primrose (Oenothera biennis) — pale yellow, but its flowers open visibly in front of you as the light fades.
• Common honeysuckle (Lonicera periclymenum) — for a fence or pergola, with scent that carries across a whole garden.
• Night phlox (Zaluzianskya ovata) — compact enough for a pot and wonderful near a door.

Making the garden work for wildlife after dark

An evening garden is at its best when it is busy. Moths such as the elephant hawk-moth and the poplar hawk-moth feed at dusk, and bats — usually pipistrelles — hunt them along hedgerows and above lawns. A few simple choices help both.

• Leave a patch of long grass and seed heads standing; it shelters insects by day and feeds them at night.
• Add a shallow water dish at ground level for hedgehogs, with a gently sloping edge so nothing drowns.
• Keep artificial light low and warm. Bright white security lights disrupt moths and deter bats. Low-level solar markers along a path are usually enough.
• Avoid pesticides. A garden full of aphids in June is a garden full of birds and insects by August.

Keeping it looking bright all season

Start the year with white tulips and Allium 'Mount Everest', follow with the roses and daisies from June, and let gypsophila carry you into late summer. Deadhead everything except the seed heads you are leaving for the birds. And on a warm evening, take a mug of tea outside and just look at it — the whole point of a white garden is that you can.