Right Plant, Right Place

The Secret to a Garden That Actually Thrives

By Ian Green, Pre-Registered Member of the Society of Garden & Landscape Designers

You’ve done the research. You’ve fallen in love with a plant at the garden centre. You’ve brought it home, planted it with care - and six months later, it looks... miserable.

Sound familiar? It happens to almost everyone, and nine times out of ten the reason is the same: the plant was put in the wrong place.

As a garden designer, the single principle I come back to again and again is right plant, right place. It sounds almost laughably simple but genuinely understanding it - and applying it - is what separates gardens that struggle from gardens that look effortless. So let me walk you through the four things I always consider before a single plant goes in the ground.

Lighting How much sun does the spot actually get?Which way is the garden facing, North, South, East or West? Is there anything that’s casts shade, such as trees?	Soil Conditions Free-draining, heavy clay, or somewhere between?
Soil pH Acid, neutral or alkaline - it matters enormously.	Final Plant Size How big will this plant be in 5 years?

1. Light - Know Your Garden Before You Plant Anything

Light is the starting point for every planting decision I make. Before I put pen to paper on a design, I understand exactly where the sun falls and, crucially, where it doesn’t.

Most plant labels describe light requirements in one of four ways: full sun (six or more hours of direct sunlight a day), partial sun or partial shade (three to six hours), dappled shade (filtered light under a tree canopy), and full shade (fewer than two hours of direct sun). These aren’t rough guidelines - they’re genuine requirements for healthy growth.

IAN’S TIP Don’t assume - observe. Spend a weekend watching your garden at 8am, 12pm and 4pm and jot down which areas are sunny, shaded, or in between. Seasons shift things too; a sunny spot in June can be heavily shaded in winter with a neighbouring evergreen tree.

One of the most common mistakes I see is planting shade-lovers like hostas or ferns in a hot, sunny spot, only to find them scorched and stressed by midsummer. Equally, planting sun-loving lavender or salvia in a north-facing bed and wondering why they never quite perform. The plant isn’t the problem - the placement is.

Some great plants for tricky spots: Digitalis purpurea (foxglove), Astrantia, and Persicaria all handle partial shade beautifully. In full sun, you can’t go wrong with Echinacea, Penstemon and ornamental grasses. For dense shade under trees, look to Epimedium, Cyclamen hederifolium, and Geranium phaeum.

2. Soil Conditions - The Foundation of Everything

If light is the first conversation I have with a garden, soil is the second - and it’s often the longer one. Your soil type dictates so much about which plants will genuinely thrive versus merely survive. The two main types you’ll encounter in most UK gardens are clay and sandy soil, with many gardens sitting somewhere on the spectrum between the two.

Clay soil holds moisture and nutrients brilliantly, but it drains slowly, becomes waterlogged in winter, and bakes hard in summer. It’s heavy to dig, but it’s actually incredibly fertile once you start working with it. Plants like Astilbe, Ligularia, and many Cornus species love these conditions.

Sandy or free-draining soil, on the other hand, warms up quickly in spring, drains fast (sometimes too fast), and can be low in nutrients. It’s a dream for Mediterranean-style planting - lavender, rosemary, Stipa grasses, Cistus - plants that are adapted to dry, lean conditions and resent having wet roots.

Soil Improvement

Adding organic matter - garden compost, well-rotted manure, leaf mould - improves almost any soil. It opens up clay and helps sandy soils hold more moisture and nutrients. But always remember: improve your soil by all means, but don’t fight your soil’s fundamental character. Work with it by choosing plants that suit it.

3. Soil pH - The Invisible Factor That Rules Your Plant List

This is the one that surprises people the most, because you can’t see it. Soil pH - the measure of how acidic or alkaline your soil is - controls how well plants can absorb nutrients, even if those nutrients are present in the soil. Get this wrong and your plants will look pale, yellow, and struggling, no matter how much you feed them.

Most garden plants prefer a slightly acidic to neutral range - roughly 6 to 7 - but there are passionate exceptions at both ends of the scale.

pH Range	Condition	Ideal Plants
4.5 – 5.5	Strongly acid	Rhododendrons, azaleas, blueberries, camellias, pieris
5.5 – 6.5	Mildly acid	Hydrangeas (blue), heathers, most conifers, magnolias
6.5 – 7.0	Neutral	Most vegetables, roses, perennials - the widest range of plants
7.0 – 8.0	Alkaline/chalky	Clematis, Fagus sylvatica (beech), Syringa (lilac), Buddleia, Salvia nemorosa, many herbs

Testing your soil pH is easy and inexpensive - simple test kits are available from any garden centre for just a few pounds, or you can send a sample to a lab for a more detailed analysis. I recommend testing a few spots across your garden, as pH can vary surprisingly between different areas.

“Understanding your soil pH isn’t just for serious gardeners - it’s for anyone who’s ever wondered why their rhododendron looks yellow or why their hydrangeas are pink despite everyone else’s being blue.” - Ian Green, Garden Designer

You can adjust pH to some degree - adding garden lime raises it, adding sulphur or acidic compost lowers it - but this is a long, gradual process.

My honest advice? Test your soil, find out what you’re working with, and lean into it. Alkaline gardens can be extraordinary. Acid gardens even more so.

4. Final Plant Size - Think Five Years Ahead, Not Ten Days

This is arguably the mistake I see most

, and it’s entirely understandable. You fall in love with a small, well-behaved shrub at the garden centre - it’s maybe 40cm tall, perfectly shaped, and fits beautifully in your border. Ten years later it’s blocking the window, swamping everything around it, and you’re hacking at it twice a year in a futile battle to keep it small.

Every plant label should carry an approximate eventual height and spread. Take these seriously. Even better, look up the plant online or in a good reference book and find out what it looks like at full maturity. That compact Viburnum tinus is lovely at the nursery; it’s also going to be 3 metres tall and 2.5 metres wide one day.

LOW	Ground cover & low perennials (under 40cm) Great for front-of-border weaving and weed suppression. Examples: Epimedium, Alchemilla mollis, Ajuga.
MID	Mid-border perennials & grasses (40cm – 1.2m) The workhorse of most borders. Examples: Salvia, Penstemon, Stipa gigantea, Echinacea.
TALL	Structural shrubs (1.2m – 3m) The backbone of a planting scheme. Check their spread carefully. Examples: Viburnum, Sambucus, Cornus.
TREE	Trees (3m+) Always research ultimate height AND spread before planting. Consider root spread near drains and buildings. Examples: Amelanchier, Betula, Prunus.

A RULE I ALWAYS FOLLOW When spacing plants, resist the temptation to cram them in for instant impact. Plant for what they’ll be in five to seven years, not for how they look on day one. A border that looks sparse in year one will be beautifully full and balanced in year three - and still manageable in year ten. Use annuals and fast-growing perennials to fill gaps in the early years.

Putting It All Together

I know it might sound like a lot to consider before you buy a single plant - but once these four factors become second nature, it genuinely transforms how you garden. You stop fighting your garden and start working with it. You spend less time rescuing ailing plants and more time simply enjoying the space.

Think of it this way: the garden centre has done you no favours if they’ve sold you a chalk-hating, moisture-loving, shade-requiring plant for your sunny, dry, alkaline border.

Understanding your garden’s conditions first means every plant you choose has the best possible chance of flourishing - naturally, with minimal intervention, exactly as it should.

And when a plant thrives in exactly the right place? There’s very little in gardening that’s more satisfying than that.

Frequently Asked Questions

How far apart should I plant shrubs and perennials?

The honest answer is: base it on their mature spread, not their size when you buy them. Check the plant label or look up the expected spread at full size, then space accordingly - typically half the combined spread of two neighbouring plants.

What fast growing plants can I use to fill gaps in a new border?

For temporary gap-filling while permanent plants establish, hardy annuals are your best friend: Cosmos, Nigella, Ammi majus, and Echinacea from seed are all fast and beautiful. Alchemilla mollis spreads quickly and can be cut back hard. Persicaria amplexicaulis is a perennial that establishes rapidly and gives brilliant colour.

Resist the temptation to plant permanent shrubs too close together to fill gaps - you'll pay for it in five years' time.

How do I test the pH of my soil?

The easiest method is a simple pH test kit from any garden centre - they cost just a few pounds and take about ten minutes. You mix a small soil sample with the indicator liquid or powder and compare the colour to a chart. For a more precise reading, you can send a sample to a soil testing lab.

I recommend testing several spots across your garden, as pH can vary between areas

How do I know if I have clay soil?

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Ian Green is a pre-registered member of the Society of Garden & Landscape Designers, offering ecological and contemporary garden design services. Based in Lincolnshire.