Key takeaways
- Give about 70% of the border to structure and foliage, 30% to seasonal flowers
- Judge the split by the space each group fills, not by counting plants
- A good backbone still looks furnished in January with every flower gone
- Repeat three to five key plants in drifts of 3, 5 or 7 along the border
- Plant flowers in drifts, never dotted singly, and keep to two or three colours
- Buy and place structure first, then slot the flowers into the gaps
The 70-30 planting rule is a simple way to make a border look good all year, not just in July. Give about 70% of the space to structure and foliage and 30% to seasonal flowers. The structure keeps the border full from autumn to spring. The flowers bring the colour when it is their turn.
Most borders do the opposite. They peak for a few summer weeks, then slump into bare soil and gaps. This guide explains the rule, how to measure it by eye, and how to apply it to any border in sun or shade. If you love a looser, romantic look, the contemporary cottage garden version of the 70/30 rule shows how it works in that style.
What is the 70-30 planting rule?
The rule splits a border by job. About 70% is structure: evergreen shrubs, grasses and good foliage plants that look decent with or without flowers. The other 30% is seasonal colour: the perennials, bulbs and bedding that flower and then fade.
The 70% is the backbone. Evergreens keep their shape under frost. Grasses catch low winter sun and stand until spring. This is the part most new borders leave out.
The 30% is the treat. Salvias, echinacea, roses and dahlias pull the eye and mark the season. They matter, but they can’t carry a border on their own.
Treat the split as a target by eye, not a sum. Roughly two thirds structure and one third colour is close enough.
Why the 70-30 rule makes borders look better
It works because much of the year has no flowers in it. A typical UK border flowers from about May to September. For the rest of the year, structure is all you have.
A strong backbone also fixes patchiness. Flowering plants bloom in waves, so something is always going over before the next thing opens. With foliage and evergreens in the gaps, the border still looks full during the changeover.
Structure gives the flowers a setting too. A dahlia against a bare fence looks lost. The same dahlia rising from a clipped mound or a haze of grass looks planned.
Gardener’s tip: Look at your border from the window in January. If you mostly see soil and a few sticks, you are short on structure. A good backbone still looks furnished with every flower gone.
Choosing plants for the 70% backbone
Spend most of your space and thought here. Choose plants that earn their place for months, not a fortnight. Look for strong foliage, a good shape and, ideally, evergreen leaves.
Three groups build a reliable backbone:
- Evergreen shrubs for year-round bulk: yew, pittosporum, hebe, choisya, euonymus and box. Box suffers from box blight and box tree caterpillar in many areas, so yew or Ilex crenata are good stand-ins for clipped balls.
- Ornamental grasses for movement and winter shape: Stipa, Calamagrostis, Miscanthus and Hakonechloa.
- Foliage perennials and shrubs to fill between: euphorbia, hardy geraniums, heuchera and viburnum.
Mix textures within the backbone. Put fine grass against a broad-leaved shrub, and glossy leaves next to soft, matt ones. That contrast stops the green framework looking like a flat wall. The guide to evergreen shrubs for year-round interest has more choices.
| Plant | Type | Job in the 70% |
|---|---|---|
| Yew (Taxus baccata) | Evergreen shrub | Dark backdrop, clipped shapes |
| Pittosporum | Evergreen shrub | Bulk and pale leaf contrast |
| Stipa tenuissima | Grass | Soft movement near the front |
| Calamagrostis ‘Karl Foerster’ | Grass | Upright accent, stands all winter |
| Euphorbia characias | Foliage perennial | Evergreen, lime-green structure |
| Hakonechloa macra | Grass | Soft mound for sun or part shade |
Warning: Euphorbia sap irritates skin and eyes. Wear gloves when you cut it back.
This is what the 70% looks like: clipped evergreens, an upright yew and grasses. It still looks good with no flowers at all.
Choosing flowers for the 30% highlights
The 30% is the bit people notice, so each plant has to work hard. Choose flowers with a long season, a strong colour or good seedheads. Ideally all three.
Good border choices include Salvia nemorosa, Echinacea purpurea, rudbeckia, achillea, roses, dahlias and Verbena bonariensis. Many flower for weeks. Several leave seedheads that act as structure once the colour has gone. The guide to the best perennial plants for UK gardens has plenty more.
Plant flowers in drifts, never dotted singly. One salvia is a spot. Seven salvias in a group read as a river of colour. Repeat that drift two or three times along the border and the whole scheme hangs together.
Keep to a plan for colour, rather than buying one of everything in flower. Two or three colours always look calmer than a rainbow. The 60-30-10 colour rule further down helps with this.
The 30% in action: salvia, echinacea and dahlias planted in groups. Drifts like these look far more planned than single plants.
Measure the ratio by area, not plant count
This is the part people get wrong most often. The split is about how much space each group fills, not how many plants you buy.
One mature viburnum can fill as much border as fifteen salvias. Count plants and three shrubs against thirty perennials looks flower-heavy. Look at the space instead and those three shrubs may fill most of the border.
Think about height as well as ground. A tall Miscanthus takes up far more of the view than its small footprint suggests.
To judge it, stand back and squint. In winter, the border should still look about 70% furnished. If it drops to mostly bare soil, add more or bigger structural plants next season.
Repetition, drifts and the rule of odd numbers
Repetition turns a collection of plants into a border. Repeating the same plant along its length creates rhythm and leads the eye. Without it, a mixed border reads as a jumble.
Pick three to five key plants and repeat each several times. A grass, an evergreen mound and one flower, each repeated three times, makes a coherent border from very few varieties. Slightly uneven spacing looks more natural than a perfect pattern.
Plant each repeat as a group of 3, 5 or 7. Odd numbers merge into natural drifts, while pairs look stiff. Single plants dotted about give the spotty look of an unplanned garden.
The same grass and evergreen ball repeated down the path. A few plants used again and again give a border its rhythm.
Layering plants by height, front to back
The basic rule is tallest at the back, lowest at the front, with mid-height plants between. It sounds obvious, but it is easy to get wrong when buying plants in small pots.
For a border seen from one side, think in three layers:
- Back: tall structure such as Miscanthus, viburnum, climbers on the fence and tall flowers like Verbena bonariensis.
- Middle: the bulk of both groups, such as salvias, grasses, hardy geraniums and medium shrubs.
- Front: low plants such as Stipa, heuchera and low evergreen edging.
Break the rule now and then. One tall, see-through plant near the front, such as Verbena bonariensis, adds depth and stops the border looking like a staircase.
For an island bed seen from all sides, put the tallest plants in the centre and grade down to every edge. In a narrow border, tighter layering keeps it feeling full, and the small garden design ideas guide has more space-saving tricks.
A 70-30 border for sun and one for shade
The rule works the same way in sun and shade. Only the plant list changes.
A sunny border might use pittosporum and Stipa for its backbone, with Calamagrostis as upright accents. The 30% comes from salvias, echinacea and a few dahlias for late colour. All of these like full sun and free-draining soil.
A shady border leans harder on foliage, because shade offers fewer flowers. Ferns, hostas and evergreen shrubs build the 70% from leaf shape alone. Foxgloves, astrantia, hellebores and Japanese anemones bring the colour. The guide to the best plants for shade has more ideas.
| Part of the border | Sunny border | Shady border |
|---|---|---|
| Evergreen structure | Pittosporum, hebe, yew | Euonymus, yew, evergreen ferns |
| Grasses and foliage | Stipa, Calamagrostis | Hakonechloa, hostas |
| Flower highlights | Salvia, echinacea, dahlia | Foxglove, astrantia, Japanese anemone |
| Winter interest | Grass seedheads, clipped shapes | Evergreen ferns, hellebores |
Pet note: Foxgloves, hellebores and euphorbia are all toxic if eaten. Most pets leave them alone, but think twice if you have a puppy that chews everything.
Adding a focal point to your border
A border needs somewhere for the eye to land. A focal point gives the planting an anchor and a sense of purpose.
It can be a statue, a sundial, a large pot, a clipped specimen or a bench. Stone pieces work well because they stand out against soft planting in every season, including bare winter. A statue like the Endless Love Garden Statue suits the end of a border, and a granite swirl sundial marks a path junction nicely.
Put it at a natural stopping point: the end of a border, a path junction, a bend in the lawn or the centre of an island bed. The planting then builds towards it.
Use only one strong focal point per view. Two features compete, and the eye doesn’t know where to settle.
A single statue at the end of the path gives the whole border a destination. The evergreens around it keep it framed all year.
The 60-30-10 colour rule for your flowers
The 70-30 rule sets the structure. The 60-30-10 rule sets the colour of the flowers within the 30%. They are separate tools that work well together.
Pick a main colour for 60% of the flowers, a second colour for 30% and an accent for 10%. A border might run purple salvia and verbena as the main colour, pink echinacea and roses as the second, and a few orange dahlias as the accent.
Holding to three colours stops a border looking busy. The green of your backbone counts too. It is the quiet background that lets the flower colours shine. For more on picking colours that sit well together, see the guide to colour wheel garden design.
Purple and pink with a little white, all set against green. A tight palette like this looks calm, and the sundial marks the junction.
Planning a 70-30 border on paper
The easiest way to hit the split is to plan before you plant. Sketch the border to scale and draw the structural plants first, as circles at their full spread. Check they cover about 70% of the area.
Then add the flowers into the gaps between and in front. Working in this order stops the usual mistake of buying flowers first and squeezing structure in later. The guide to writing a planting plan walks through the drawing step by step.
On planting day, set the pots out on the soil and walk to the far end of the garden. It is much easier to shuffle pots than to dig up shrubs. A photo on your phone flattens the scene and shows the balance honestly.
Space shrubs for their mature size. They will look sparse for a season or two. Fill short-term gaps with annuals rather than overplanting.
Standing back with a notebook makes the balance easier to judge. Set pots out and look before anything goes in the ground.
Common 70-30 border mistakes
Too many flowers. Buying whatever is in bloom at the garden centre pushes the flower share well past 30%. The border looks great in June and bare by November. Buy structure first.
Dotting single plants about. One of everything spreads colour too thinly and kills any rhythm. Plant in odd-numbered drifts and repeat a few key plants instead.
Counting plants, not space. A few big shrubs can fill the backbone while lots of small perennials make the flowers. Judge by the space each group fills.
Forgetting winter. Ask what each part of the border looks like in January. Evergreens and grasses with standing seedheads keep the bones on show.
No focal point, or too many. One clear anchor per view is enough.
Your 30% feeds the bees too. Echinacea is a reliable border flower that pollinators love from midsummer.
Frequently asked questions
What is the 70-30 planting rule?
About 70% of a border is structure and foliage, 30% seasonal flowers. The structure is evergreen shrubs, grasses and good foliage plants that look decent all year. The flowers add colour for their few weeks or months. Get the balance right and the border stays full when the flowers go over.
Is the 70-30 rule measured by plant count or area?
By the space each group fills, not the number of plants. One mature shrub can fill as much room as a dozen small perennials. Stand back and judge how much ground and height each group takes up, rather than counting pots.
What plants make good backbone structure in a UK border?
Evergreen shrubs, ornamental grasses and plants with strong foliage. Yew, pittosporum, hebe, choisya and box give evergreen bulk. Grasses such as Stipa, Calamagrostis and Hakonechloa add movement. Euphorbia, hardy geraniums and heuchera fill the space between.
How do I use the 70-30 rule in a shady border?
Build the 70% from shade-loving foliage such as ferns, hostas and evergreen shrubs. Add the 30% colour with foxgloves, astrantia, hellebores and Japanese anemones. Shade has fewer flowers on offer, so leaf shape and texture do most of the work.
What is the rule of odd numbers in planting?
Plant perennials and grasses in groups of 3, 5 or 7. Odd groups read as natural drifts and knit together. Even numbers tend to look paired and stiff. The rule matters less for big shrubs that stand on their own.
How is the 60-30-10 rule different from 70-30?
The 60-30-10 rule is about colour, not structure. It gives 60% of the flowers to a main colour, 30% to a second and 10% to an accent. Use 70-30 for the framework, then 60-30-10 to plan the flowers within it.
Why does my border look patchy and bare in winter?
It is probably too flower-heavy and short on permanent structure. Herbaceous perennials die back to bare soil after flowering. Add evergreen shrubs, clipped shapes and grasses with standing seedheads until they fill about 70% of the space.
Where should the focal point go in a 70-30 border?
Put one focal point where the eye naturally stops. The end of a border, a path junction or a bend in the lawn all work. A statue, sundial, large pot or bench gives the planting an anchor. One per view is plenty.
Now you know the ratio, read the guide to planning a mixed border to put it into practice, or browse more garden design ideas.
Our team produces practical UK gardening guidance from source research, contributor records and established horticultural practice. Editorial standards are overseen by Matt W.
