Choosing A Colour Scheme For Mixed Borders

Why a colour scheme matters more in a small or coastal plot

In a long country border, a muddle of colours can almost get away with it — the eye reads the planting in sections as you walk past. In a narrow seaside garden or a courtyard you can see in one glance from the kitchen window, it cannot. Small spaces are taken in all at once, and coastal light is famously unforgiving: bounced off water, pale walls, shingle and sky, it bleaches soft pastels and exaggerates anything that clashes.

That is not a reason to be timid. It is a reason to be deliberate. A border with a clear colour scheme looks designed even when it is stuffed with plants, and it holds together from March to October rather than peaking for three weeks in July.

Choose three colours, then one wildcard

Aim for a palette of three main colours plus a single accent. The classic proportion is roughly sixty per cent of one colour, thirty of the second, and ten of the accent. Crucially, foliage counts as a colour. Silver leaves — lavender, santolina, artemisia — behave as a colour and as a separator, cooling hot combinations and lightening dark ones.

Some schemes that work well in British conditions:

• Blue and yellow with silver. Nepeta, hardy geranium, alchemilla and verbascum against pale yellow achillea and a silver edge. Gentle, cottagey, and tolerant of part shade.
• Hot spice. Crocosmia, helenium, penstemon and geum in oranges, rusts and crimsons, cooled with a little dark purple. Needs full sun and strong light to carry it off.
• White, green and bronze. Japanese anemone, white cosmos, bronze sedum and grasses. Works in shade and looks expensive in a small courtyard.

The wildcard is the plant that surprises without breaking the rules — a single clump of something deep burgundy or acid lime, repeated no more than twice.

Let texture carry the contrast

Once the hues repeat, texture does the work of keeping the border lively. Think in three groups and make sure your palette appears in more than one of them:

• Spiky and sword-like: iris, crocosmia, eryngium, kniphofia.
• Soft and mounded: alchemilla, hardy geranium, catmint, heuchera.
• Fine and airy: stipa, deschampsia, verbena bonariensis, fennel.

A blue that appears as a mounded geranium, a spiky eryngium and a haze of verbena reads as a deliberate theme rather than an accident. In a small space, plant fewer varieties in bigger drifts — a full metre of one plant will always look more considered than fifteen different things in a row.

Plan seasonal peaks, not one big summer

Most mixed borders look magnificent in July and thin everywhere else. Plan for three or four peaks instead, and check that at least one plant in each peak carries one of your palette colours.

• Late winter to spring: hellebores, snowdrops, narcissi and early tulips. Coastal gardens warm slowly, so choose late-flowering tulips that miss the worst of the wind.
• Late spring to early summer: alliums, bearded iris, aquilegia, the first roses and nepeta.
• High summer: crocosmia, helenium, penstemon, eryngium, verbena and the grasses.
• Autumn: asters, sedum, Japanese anemone, and seedheads left standing for structure and for the birds.

If a gap appears, do not fill it with whatever happens to be on the bench. Fill it with a plant in a colour you have already used.

Repeat plants to stitch the border together

Repetition is what makes a scheme look intentional. As a working rule, every plant in a border should appear at least three times, spaced along its length rather than clumped in one corner. In a small plot, repeat a plant every two metres or so; the eye picks up the rhythm and reads the whole border as one composition.

It helps to have a bridge plant that carries two of your colours at once — a purple-blue nepeta linking blue and pink, or a bronze sedum linking purple and orange. Use the same plant in a container at each end of the border to frame the view, which is particularly effective in a courtyard where the planting is seen through a doorway.

Working with salt, wind and shade

Coastal conditions shape both the plants and the colours. Wind shreds soft foliage, so favour leathery, narrow or silver-grey leaves that shrug off salt. Because sea light is so bright, colours are diluted — deepen your palette by a shade or two compared with an inland garden, and avoid very dark purples altogether, which turn black in full glare.

Small spaces bring their own constraints. Walls and fences cast shade, so put white, cream and pale yellow at the shaded end where they will glow, and save the hot oranges and reds for the sunniest stretch. Keep upright accents — a single verbascum, a tall allium — to add height without width, and let the repeated colours do the rest of the work.