Hedges & Screening: How Tall, How Far Apart, What Plant

The brief arrived by email: thirty two metres of evergreen hedge along the back and side boundary of a new stand in one of the Klapmuts estates, for privacy, could we quote. We went out with a garden cane before quoting anything, because a hedge is the one job we will not price off a photograph.

Sitting at the patio table, the only thing anyone could actually see was one first floor window on the stand behind, and at night the headlights swinging across the north corner off the link road. The rest of the thirty two metres was screening a view of nothing in particular, from a part of the garden nobody sat in. What we planted was seven metres.

Most people who ask us for a hedge want a screen, and the two are different jobs. A screen removes one sightline. It can be short, it can be close to you, and it can be up this week. A hedge is a clipped wall of plants along a line, and somebody trims it twice a year for as long as you live in the house.

Whichever you are building, the plant is the fourth decision, not the first. By the time you get to choosing it, the height, the position and the spacing have already decided whether the thing works. Nearly every hedge article ever written starts at the fourth decision. This one runs in the order the job actually runs: how tall, where, how far apart, and only then what plant.

Why hedges fail, and why it takes three years to show

A hedge gives you no feedback. A lawn tells you within a fortnight. Paving tells you in the first wet winter. A hedge looks fine for three years and then tells you about a decision you made on planting day and can no longer revisit. That is the whole reason the planning half of this article is longer than the planting half.

A hedge and a screen are different jobs

A hedge is a clipped continuous plant wall, usually along a boundary, and it is a commitment of two to three cuts a year for as long as it stands. A screen is anything that removes a sightline. A hedge can be one, but so can three shrubs, one multi-stem tree, a batten panel, a trellis with a climber, or a raised bed with tall grasses on it.

• ✓Choose a hedge when you want the line itself as a design element: a formal face, a crisp edge to a lawn, a wine-farm look, or when the whole boundary genuinely needs to go.
• ✓Choose a screen when there is one window, one gate, one gap or one seat that is the actual problem. In our experience that is most of the time.

Our landscaping ideas guide asks how much privacy you want and how tall the screening needs to be. This article is the answer to that question.

Step 1: Find the height with a garden cane, not a catalogue

Two people, a garden cane or a broom, and a tape measure. Sit where you actually sit, at the hour you actually sit there. The second person stands where the screen would go and raises the cane until the thing you want gone disappears behind their hand. Mark it, measure it. That number is your finished height.

Ten minutes, no cost, and it is the only measurement on this page that is specific to your garden. Do it twice, once at the boundary and once about two metres from your seat, and the difference between those two numbers is the entire argument of this article.

The geometry, without the algebra: the height a screen needs is set by how high your eye is, how high and how far away the problem is, and how far the screen is from you. Move the screen towards you and it gets shorter fast, because a sightline is a straight line and you are intercepting it earlier. The eye heights we work to are about 1.2m seated on a patio, about 1.5m at a kitchen sink, and about 1.6m standing.

Read the second and third rows again. A first floor window needs a 3.1m hedge on the boundary, which is a ladder job forever, or a 1.7m screen two metres from your chair, which one person trims from the ground. Same window, same chair. The only thing that changed is where the screen stands.

Step 2: Decide where the line actually goes

Six decisions, each with a number or a rule behind it.

1. 1Near you or on the boundary. Near costs you garden and light. The boundary costs you height and reach, forever. Step 1 tells you what that trade is worth in millimetres.
2. 2Distance off structures. Keep the trench centre 0.6 to 1.0m off a boundary wall for a shrub hedge. Never put anything that wants to be a tree within about 3 to 4m of a wall, a paved edge, a drain or a soakaway. Our paving guide sets out the root rule for trees near hard surfaces, and it applies just as much to a hedge line.
3. 3Services. A hedge trench is a continuous 400mm deep excavation the length of a boundary, which is exactly where irrigation mains, electric fence feeds, gate motor cable and stormwater tend to run on a new stand. Find them before the spade goes in, not with it.
4. 4The neighbour's side. A hedge grows in both directions, somebody has to reach the far face to cut it, and the roots, the shade and the leaf fall land on both properties. Agree access before you plant, because a hedge you cannot reach the back of is lopsided within four years. We are describing what is physically true here, not giving legal advice.
5. 5Estates. Val de Vie has a strong architectural and landscaping code with approved plant palettes, and at Pearl Valley private gardens and the shared landscape are meant to read as one. Check with your estate before you order, because a boundary planting is exactly the kind of thing those codes cover.
6. 6Shade cast onto your own garden. A 2m evergreen face on a north or west boundary throws a real shadow, and what is under it is usually lawn. If that is the plan, the shade-tolerant end of our grass types guide matters more than it did yesterday.

Step 3: Set the height and width, and check you can reach it

Design the hedge so it can be topped from the ground. In practice that means a finished height of about 1.8 to 2.0m for most people. If the geometry in step 1 demands more than that, move the screen rather than raising it.

The reasoning is economic rather than aesthetic. A hedge you can top from the ground is one person with a trimmer and a rake. A hedge at 2.5m or 3m is a ladder or a platform, a second person on the ground for safety, and longer on site. And it is that way at every single visit, for the life of the hedge. The height decision is not a one-off cost, it is a permanent multiplier on a recurring one, and almost nobody is told that before they plant.

Width gets forgotten entirely. A clipped shrub hedge finishes about 0.6 to 0.9m wide at the base, and a fast screen species held at 2.5m wants closer to 1.0m. Two consequences: the trench has to be about 600mm wide so the root plate is not sitting half in unbroken ground, and the hedge eats about half a metre of usable garden on your side plus whatever grows over the line. On a townhouse boundary that is a real amount of garden, and it is sometimes the reason a panel beats a hedge outright.

Step 4: Spacing, the mistake that hides for three years

Spacing is centre to centre along the line, and it is the decision that becomes permanent soonest.

There are two failure modes and the received wisdom only warns about one.

Too wide is the failure the books cause. They tell you to space at the mature spread, which is right for a specimen shrub and wrong for a hedge, and you wait eight years for a screen. Too tight is the failure the nurseries cause, and it is the worse of the two because it hides for longer. The plants close over the top in year three and everybody is delighted. Then from about year six they are competing for the same water and the same light in the same 600mm trench, the base thins, and there is no fix that does not involve pulling plants out of an established hedge, which never looks right again.

Step 5: Now choose the plant

Two columns matter more than the rest and no commodity plant list carries either. Growth, because it converts into years to close at the spacing you chose. And recovery from a hard cut, because it decides whether this hedge can ever be renovated or whether it is a replacement the day it gets away from you.

Roughly: a fast screen at 0.8m centres from 4L stock closes in two to three summers, a moderate shrub at 0.5m centres in three to four, and a slow formal hedge in five to eight.

Notes worth having before you order. Carissa is thorny, which is the point on a boundary and a genuine nuisance beside a path, a play area or anywhere someone has to reach in to trim it. Coleonema, Westringia, rosemary and lavender are all short-lived by hedge standards, roughly five to eight years for Coleonema and four to six for lavender, so treat them as a low hedge you will replace rather than a permanent structure. Viburnum is the one on this list that will genuinely hold a dense face in shade. For the natural sizes, flowering and habits of the indigenous species here, our water-wise planting guide has more, and SANBI's PlantZAfrica is the best free reference there is.

What we will not plant on a boundary, which tells you more than the list above. Not Ficus, and we are correcting our own landscaping ideas guide here, which has recommended it for boundary screening: the roots lift paving and crack walls, which is one of the reasons trees end up on our felling list in the first place. Not conifers, because none of them break from old wood, so a conifer hedge that gets away from you is a removal rather than a renovation. Not fynbos: proteas, ericas and restios are wonderful plants and they do not make hedges, so do not ask them to. And in Franschhoek, which sits higher and colder with the occasional frost, check frost tolerance before committing to a long run of anything tender.

Step 6: Dig a trench, not a row of holes

A hedge goes into a continuous trench about 600mm wide, worked to about 400mm deep, which is the depth our soil guide already sets for a hedge or a small tree.

Why a trench and not holes: a hedge is not a row of shrubs, it is one root community, and within three years those roots occupy the whole line whether you prepared it or not. A row of holes augered into unbroken ground gives you a row of pots, each plant in a soft pocket with a wall of untouched ground around it, which is exactly the failure our soil guide describes for a tree planting hole.

That deserves resolving rather than glossing over, because the two pieces of advice sound contradictory. The objection to an improved planting hole is the pot: a rich island with a hard wall around it. A continuous trench has no wall in the direction the hedge is trying to grow. So the trench is the cure for the pot problem rather than another instance of it. Improve the whole line evenly, or improve none of it, and never improve one plant's worth of it. Our compost calculator works from area, and a metre of 600mm trench is 0.6 square metres, so multiply your run by 0.6 and it will size the material.

1. 1String line first, and check it from both ends before you dig.
2. 2Trench the full run at 600mm wide, and break whatever the spade stops on rather than working above it.
3. 3Get any rubble out. Burying it deeper is not preparation.
4. 4Backfill with what came out plus compost worked evenly along the whole line, and firm it.
5. 5Lay every plant out in its bag along the line and count before a single one goes in. Metres divided by centres should equal the number of plants on the ground.
6. 6Plant to the same depth it sat in the bag, firm properly because a rocking plant never roots, and water in immediately.

Step 7: The first two summers decide the next twenty

This is the one place a new hedge argues with our own water-wise advice, so we will say it plainly. Our Paarl water-wise guide puts boundary planting in the lowest water zone, a deep drink once a fortnight in summer and nothing in winter. That is right for an established boundary and wrong for a new hedge. A new hedge is a high-water line for its first two summers and only becomes a low-water line afterwards, which is exactly why it wants its own valve rather than being tacked onto the boundary zone.

• ✓A 16mm line down the centre of the trench, with a second offset line for anything over about 0.8m wide at the base.
• ✓Emitters at 2 L/h spaced at 300mm along the line, rather than the wider spacing used for individual shrubs. You are wetting a continuous strip, not a set of plants.
• ✓Line under the mulch, never on top of it.
• ✓Its own valve, so you can drop the run back to the boundary schedule in year three without re-plumbing anything.

Our guides to drip irrigation and garden irrigation systems cover the parts and the zoning, the watering calculator does session length, and our irrigation team sets up establishment valves as routine.

Step 8: Cut it in the first year, before it reaches height

Almost nobody does this, and it is the reason so many hedges are thin at the bottom. The instinct is to leave a young hedge alone until it reaches the height you want and only then start clipping. That produces a hedge that is dense at the top, where the growth was tipped, and open at the bottom, where it never was. The bottom is the half you wanted.

Tip the leading growth from the first season, repeatedly, while the plant is small. You are trading a year of height for a base that is still solid in year fifteen.

On timing, our garden calendar already pins the first shaping of the year to September and rules out winter cutting. What it does not give is the number of cuts and their spacing, so here it is: a crisp formal face wants two to three cuts, September and again in January, with a third in late autumn only on a vigorous species. An informal screen wants one, after flowering where it flowers. Keeping that rhythm is most of what our garden maintenance rounds do on a hedge.

Step 9: Trim it so light reaches the bottom

Clip the hedge with the top narrower than the base. A slight A profile, roughly 100 to 150mm in on each side over a 2m face.

A hedge clipped dead vertical shades its own lower half. A hedge clipped wider at the top than the bottom, which is what happens by default because the top is where a trimmer reaches most easily, shades it completely. That is the whole explanation for almost every bare-bottomed hedge in the Winelands. It is entirely preventable, and it is only preventable while the hedge is young, because you cannot restore a base that has been dark for six years.

1. 1Sides before top.
2. 2Bottom to top on each face, so the cuttings fall clear of what you are about to cut.
3. 3String line at the finished height for a formal face.
4. 4Cut into the current season's growth, not back into bare wood.
5. 5Sight along the length from one end before you stop. A hedge is judged along its length and never from square on.

The five checks you get one chance at

1. 1Before you buy anything: the cane test, from where you actually sit, at the hour you sit there. Write the number down.
2. 2Before the trench is backfilled: tape in it, 600mm wide and 400mm of workable depth, and photograph it. That is the only record of the trench that will ever exist.
3. 3Before a single plant leaves its bag: lay them all out along the string line and count. Metres divided by centres should equal the plants on the ground.
4. 4Monthly through the first two summers: pull the mulch back and dig 150mm. Wet at 150mm, or the establishment line is not working.
5. 5At every trim from year one: stand at one end and sight along it, and check the top is narrower than the base.

What a hedge costs, and the part nobody prices

Our landscaping ideas guide puts planting a bed at R150 to R500 per square metre as a rough 2026 planning range, including plants, compost and mulch. A hedge trench 600mm wide is 0.6 square metres of bed per running metre, so a planted hedge lands somewhere around R90 to R300 per running metre on the same basis: more at the tight spacings a formal hedge needs, less on a wide-spaced screen line.

Then the part nobody prices. Trimming is quoted per visit, and the price is driven by three things that have nothing to do with how many plants you bought: metres of face, whether it can be cut from the ground, and how the arisings get off the property. That is why step 3 spends so long on reach. Our tree felling cost guide gives the order of magnitude for skilled cutting work, though note those figures are per tree rather than per metre.

The framing worth carrying away: a hedge is the one thing in a garden you buy once and pay for forever. Two trims a year for twenty years is forty visits, and exactly one payment in that whole sequence was for plants. That is not an argument against hedges. It is an argument for designing one you can reach, at a length you actually need, which is what steps 1 to 3 are for. Our garden maintenance service covers hedge trimming on a schedule, and we are happy to quote a trim before you plant so you know the number. Ask us.

Wind, noise, and the two things a hedge is quietly good at

Our landscaping ideas guide says the south easter shapes more Cape gardens than people realise, and then does not say what to do about it. Here is the answer, and it is counter-intuitive: a permeable screen shelters better than a solid wall.

Air cannot go through a wall, so it goes over it and comes down hard just behind it. That is why a walled patio is often gustier than an open one and why pots blow over against walls. A hedge lets roughly half the air through, which bleeds the energy out of it rather than deflecting it, and gives useful shelter downwind for something in the order of eight to twelve times its own height. A 2m hedge therefore does real work across sixteen to twenty four metres, which on most Winelands stands is the whole garden.

Noise is the opposite, and we will be straight about it because plenty of people are not. A hedge of domestic thickness takes very little off traffic noise. A solid wall does more. What a hedge genuinely does is hide the source, and hiding the source changes how much the noise bothers people, which is a real effect and not the same thing as blocking it. If noise is the brief, build the wall and plant in front of it, and our landscaping team will price both halves.

Renovating a hedge that got away

Three questions, in order.

1. 1Does this species break from old wood? The second table above answers it. Wild olive, Searsia, Carissa, Viburnum, Buddleja and most broadleaved evergreens do. Coleonema, Westringia, rosemary, lavender and every conifer on the market effectively do not, and a hard cut on those is a removal with extra steps.
2. 2How bare is the base? A hedge that has been dark at the bottom for six years has no dormant buds left down there to break.
3. 3Is it still a hedge, or has it become a row of small trees? That is a different job, and it belongs to our tree felling and pruning service, with costs in the felling cost guide.

For a species that does recover, the method runs over three years and never in one go. Cut one face hard back to the framework in September, and leave the other face and the top untouched so the plant keeps feeding itself. Feed and water it through that summer. Do the second face two years later, and the top last. A whole hedge cut hard on every face in one season is a gamble even on a species that tolerates it.

A Klapmuts boundary, and the seven metres that did the work

Back to the job at the top. The cane test was done from the patio chair at six in the evening, which is when the owner actually uses the space. Eye height seated about 1.2m. The neighbour's first floor window sill measured about 3.6m above the patio and sat about 14m away.

On the boundary, 11m from the chair, the screen would have had to finish at about 3.1m to lose that window. Set 2.5m off the patio edge, it had to finish at about 1.6m. Same window, same chair. Only the position changed.

What went in: seven metres of clipped screen at a finished 1.8m, set 2.5m off the patio, in Searsia crenata, twelve plants at 0.6m centres, bought as 4L stock in March. Plus a four metre batten panel on the patio side for the first two seasons, so there was privacy that week rather than in year three, which came out in the third summer once the planting had closed. Plus three Buddleja saligna in the north corner for the headlights, unclipped at 1.0m spacing, because nobody looks at that corner in daylight and an informal block does the job on one trim a year.

The trench was 600mm wide, worked to 400mm. The spade stopped at about 160mm on the building platform along the whole line, which is the same find our soil guide describes on new-build ground. We broke it by hand, lifted about 0.3 cubic metres of brick and plaster offcut out, and backfilled with what came out plus compost worked evenly along the line rather than into twelve individual pockets. Water was its own valve, a 16mm line down the centre with 2 L/h emitters at 300mm, under 60mm of bark, run as a high-water zone for two summers before it was dropped back.

The first cut came in the first September at about 0.6m, which the owner had to be talked into, because the plants were only just starting to look like something. Second September tipped at about 1.0m, third at about 1.4m, and it has been held at 1.8m since. Two spares from the same batch went into a spare corner of the garden, and one of them went into the run in year four when a plant died over a wet winter, matched in age and size, and the gap closed in a season.

In this article's own terms: thirty two metres at three plants a metre would have been about ninety six plants and about nineteen square metres of prepared trench. What went in was fifteen plants and about four and a half. The standing cost is the sharper number though. Two trims a year on seven metres of face a person reaches from the ground, against two trims a year on thirty two metres, part of it above head height, for as long as the family lives there. Our landscaping team did the install and our maintenance round has cut it ever since.

Two lessons. The difference between thirty two metres and seven was found with a garden cane in ten minutes, before anything was bought, and no plant choice on earth would have made the thirty two metre version the better answer. And the honest limit: the seven metre screen works from the patio and the kitchen table, and it does not make the whole garden private. Standing at the far corner of the lawn you can see that window perfectly well. The owner knew that before we planted and decided it was not a problem, and that conversation is what makes the whole approach legitimate rather than a trick.

Your hedge year on one page

The one-line rule: plant in autumn, cut in September, cut again in January, and never in winter. Our Western Cape garden calendar covers the rest of the garden's year, and our soil guide covers the trench.

When we tell people not to plant a hedge

• ✓When the run is under about four metres. Three shrubs in a row is three shrubs, and it will always read as an unfinished intention. Use one multi-stem tree, a panel, or a group planting.
• ✓When the brief is noise. Build the wall, then plant in front of it.
• ✓When nobody is going to trim it. An unclipped hedge is not a low-maintenance hedge, it is a row of shrubs growing into each other, and within six years it is a renovation or a removal. Plant an informal mixed border instead, which looks deliberate when it is loose. We would rather sell a smaller planting we keep for fifteen years than a boundary hedge abandoned in year four.
• ✓When you want it now. The panel now, with planting behind it, is the honest answer.
• ✓Under a mature tree or against a shaded south boundary, because there is not enough light to build a dense base and you will get exactly the thin-bottomed hedge this article is about. Viburnum is the closest thing to an exception.
• ✓Where a wall would simply be better. A boundary that needs security, or a narrow run where you cannot give up half a metre of garden, is a wall with something planted against it.

Everything above is really one idea. How tall, where, and how far apart are decided before you choose a plant, and all three are permanent long before they look permanent. If you take nothing else from this, take the cane test in step 1 and the count against the string line in step 6.

We plant, shape and maintain hedges and screening across Paarl, Klapmuts, Simondium and the Winelands, and our garden maintenance rounds keep them cut at the right height at the right time of year. We are just as happy to walk your garden with a cane and tell you that seven metres will do what you asked thirty two metres to do. Send us your boundary length and we will come and look at it.