Simple Rock Garden Ideas: Stopping Weeds Coming Up Through Gravel

Every rock garden is sold on the same promise: spread some stone, plant a few succulents, never weed again. Two summers later the gravel is grey with dust, there is a couch running through it, and pulling anything out means fighting a sheet of shredded black plastic. The garden did not fail because rock gardens do not work. It failed because the first thing almost everybody does is roll out weed mat, is the wrong first move.

Explore the ranking pages and you get photographs; this is a long piece because a rock garden is one of the few garden projects where the boring decisions genuinely determine the outcome. Get the depth, the edges and the plant spacing right and you have a low maintenance garden that looks better every year. Get them wrong and you have bought two tonnes of stone that you will spend a decade picking weeds out of.

Why weed mat is the wrong first move

The advice you will read everywhere is to use a weed barrier fabric to suppress weeds in a rock garden. Australian horticulturists are, for the most part, against it, and they are unusually direct about why.

Kate Wall, a Brisbane horticulturist, told ABC News in August 2024 that plastic weed mat is “a short-term solution at best”, and explained the failure mode precisely: “As soon as you build up a little bit of soil on top of that, the seeds land on top of it and the roots will go straight through it, making the weeds twice as difficult to pull out.”

Gardening Australia presenter Tino Carnevale is blunter: “the weeds always find a way and trying to pull weeds out from anaerobically decomposing carpet/weed mat is a gross job.” Sustainable Gardening Australia’s position is one line “SGA does not recommend their use.”

The mechanism explains why the fabric feels like it is working for a year and then stops. Weed mat blocks weeds coming from below. Within a season or two, dust, leaf litter and windblown seed build a thin layer of organic matter in and on top of the stone a seedbed sitting above the fabric. The weeds that grow in it root down into the mat and through it, and are now anchored in something you cannot cultivate and cannot remove without lifting the whole bed.

Meanwhile the fabric blocks organic matter and worm activity from reaching the soil, degrades under UV and shreds, and turns every future planting into surgery.

There is one honest exception, and it is a different job. Gardening Australia has demonstrated laying geotextile under a gravel path not to control weeds, but as a separation layer to stop the gravel sinking into the subgrade. Under a path or a driveway base, that is legitimate engineering. Under a planted garden bed, it is a decision you will regret.

What actually suppresses weeds

Four things, in order of how much work they do.

Depth. Australian suppliers converge on 50–75mm of gravel as the range that genuinely suppresses germination, with 50mm treated as the safe minimum. Below that, light reaches the soil and seeds strike. The single most common reason a gravel bed weeds up is that it was laid at 25 or 30mm to save money, and then thinned further as stone migrated into the lawn.

Edges. Gravel migrates. Every stone that walks into the lawn or the path is a stone no longer contributing to depth, and the thin patch it leaves behind is where the first weeds appear. Steel or aluminium edging at around $25 a linear metre, set proud of the surrounding surface, is not decoration, it is what keeps the 50mm at 50mm.

Plants closing the ground. This is the one people skip. A rock garden planted at showroom spacing, with tidy gaps of bare gravel between every plant, is a weed bed with rocks on it. Plant so that the groundcovers will knit within two seasons and there is very little open ground left for anything to germinate into. Dense planting is the only weed control that gets better with time instead of worse.

Litter removal. Blow or rake the leaves out before they break down in the stone. It is the difference between gravel that stays clean and gravel that slowly turns into soil.

One genuinely well-evidenced benefit while we are here: the brief’s claim that a shallow layer of gravel around plants helps retain moisture and suppress weeds is the best-supported statement in it. A Department of Primary Industries and Regional Development trial in Western Australia found that 20mm of gravel cut evaporation from 1,618g to 543g over 107 days about 61mm of water saved. The critical condition is that it stays on the surface: as DPIRD’s David Hall put it, “Once incorporated, there will be little or no benefit from the mineral mulch.” Rake it back, do not dig it in.

The weeds you will actually get

In an Australian gravel bed the recurring offenders are oxalis, nutgrass, running grasses like couch and kikuyu invading from an adjacent lawn, wandering trad in damp shade, and whatever annual seed the wind delivers. The running grasses are why edging matters more than fabric couch travels by rhizome under a barrier. Oxalis and nutgrass regrow from underground structures, so pulling the top off achieves nothing.

Glyphosate remains registered in Australia and on the shelf in 2026; council restrictions apply to council land, not to homeowners. Boiling water works on seedlings in gravel. Flame weeding is useful and genuinely restricted during a declared Fire Danger Period or on a Total Fire Ban day it ranges from permit-required to prohibited, and the rules differ between the CFA, the RFS, the CFS and your council.

Buying the rock

This is where most of the money goes, and where the biggest avoidable mistake is made.

Bulk versus bags

Bagged decorative stone at Bunnings is about $14.11 for 20kg $705.50 a tonne. The same product in bulk from an Australian landscape yard is $147–$166 a tonne.

The crossover is roughly 185kg: about ten bags, or 2.3 square metres of bed at 50mm. Above that, bulk wins enormously. A 20 square metre rock garden at 50mm needs about 1.6 tonnes $1,128 in bags against roughly $366 delivered in bulk, which is more than the entire rest of the project. Buy bulk unless the bed is tiny or a truck cannot reach you; if access is the issue, price a bulk bag delivered by hiab before committing to fifty trailer trips.

The names Australian yards actually use

“Pea gravel” is only partly an Australian term. Some Perth and Sydney yards use it, but it appears nowhere in the decorative gravel catalogues of several of the biggest suppliers on the east coast. The Australian default for that look is 10mm river pebble.

The products you will actually be choosing between:

• River pebble rounded, in 10mm, 14mm and 20mm, plus garden pebble at 40–70mm. The classic decorative gravel; rolls underfoot and migrates more than angular stone.
• Decomposed granite angular, compacts to a firm surface, good for paths.
• Blue metal crushed basalt, cheap and very dark, which matters more than people expect.
• Scoria volcanic, light at about 1.08 tonnes per cubic metre, so a tonne goes further.
• Sandstone the standard Australian feature rock, sold loose by the tonne from 150 to 600mm.
• Quartzite, ironstone and Lilydale toppings local stone almost always looks more settled than imported.

Working out how much to order

The formula is simple and worth doing yourself, because online calculators get it wrong. One Australian calculator’s coverage figures are out by a factor of twenty.

Tonnes required = area in m² × depth in metres × bulk density in tonnes per m³.

River pebble runs about 1.5 t/m³. So 20m² at 50mm is 20 × 0.05 × 1.5 = 1.5 tonnes, and you order 1.75 to allow for uneven ground and settling.

Working the other way, one tonne of river pebble covers roughly:

• 22 m² at 30mm
• 17 m² at 40mm
• 13 m² at 50mm
• 9 m² at 75mm

That table is also an argument for depth. Going from 30mm to 50mm costs you about a third more stone and buys you the weed suppression the whole project depends on.

What a rock actually weighs

This is the number that decides whether you are doing this yourself. Sydney sandstone runs about 2,400 kilograms per cubic metre, which produces these worked weights for roughly spherical rocks:

• 300mm across about 34kg. One strong person, or two sensible ones.
• 500mm across about 157kg. Two people cannot lift this safely. It is a trolley, a plank and a lot of patience, or a machine.
• 800mm across about 644kg. Machine only.

You will read that SafeWork sets a 20 or 25 kilogram lifting limit. It does not the SafeWork NSW code says plainly that “There is no safe weight set for all workers in all circumstances.” The trade’s language is more useful: yards grade feature rock as “one-man” and “two-man” rocks.

For anything above about 300mm, price a mini excavator for a day or pay a landscaper to place them. A rock that has to be dragged into position ends up wherever it stops rather than where it belongs, which is exactly how a rockery ends up looking like a pile.

Where the rock comes from, and where it must not

Australians routinely assume rocks in the bush, a creek or a paddock are free for the taking. They are not. In New South Wales, removing rock from a national park carries penalties to 50 penalty units around $5,500. In Queensland the maximum under the Nature Conservation Act reaches 3,000 penalty units, and Queensland Parks explicitly names stacking rocks into a sculpture as an offence. Creeks, rivers and roadside reserves are separately protected.

There is an ecological reason too. Bushrock removal has been a listed Key Threatening Process in New South Wales since 1999 surface rock is habitat for reptiles and invertebrates, and once a slab is lifted the microhabitat under it does not come back. Stripping lizard habitat from the bush to build a rockery you hope will attract lizards is worth sitting with.

The legitimate cheap sources: quarry seconds, reclaimed sandstone from demolition, spoil from a neighbour’s excavation, and the classifieds. Check reclaimed stone is not rendered, painted or caked in mortar.

Placing the rock so it looks like it belongs

The difference between a rock garden and a pile of rocks is almost entirely in the placement, and there are three conventions worth knowing.

Group in odd numbers. Grouping rocks in odd numbers creates a more natural look, a design convention rather than a law of nature, but it works for the reason odd numbers work in any composition: an even group reads as deliberate pairing, an odd one reads as accident.

Bury about a third. A rock sitting on the surface looks delivered. A rock with a third of its bulk below grade looks like it was always there and the soil washed away around it. This is the single highest-value five minutes of work in the whole project.

Follow the bedding. On sedimentary stone like sandstone, the layers should run roughly horizontally and consistently across the whole group, because that is how the rock sat in the ground. One rock set with its bedding planes vertical while its neighbours run horizontal will look wrong even to someone who cannot say why.

On mixing different rock types adds visual excitement Australian designers largely disagree, arguing for one cohesive local stone on the grounds that mixed stone reads as a sample board rather than a landscape. A mixture of larger and smaller stones enhances the visual appeal of rock gardens, mixing rock sizes can create visual depth and reduce heavy planting needs, and layering different rock sizes mimics natural landscapes and adds dimension all sound. Mixing sizes of one stone is what makes a rockery read as geology; mixing types is where it goes wrong. Rock gardens can create a unique focal point, and creating a rock garden can add texture, structure, and interest both easier with three well-set rocks of one stone than fifteen of five.

Terraces, slopes and the point where it becomes a wall

Terraced rock gardens create defined planting zones, and terraced rock gardens prevent soil erosion effectively this is the better-supported of the erosion claims, because terracing shortens the slope length and gradient and gives plants somewhere to establish.

Two cautions. First, in New South Wales a retained height above 600mm stops being landscaping and becomes a retaining wall subject to development controls, and the equivalent thresholds exist in every state. Second, and less obvious: South Australian batter design guidance says rock “should be avoided as near-surface materials” on a slope, because near-surface rock prevents the stabilising vegetation from establishing. Rock on a batter looks like erosion control and can be the opposite. Plant the slope; use rock to hold the planting, not to replace it.

The general claims that rock gardens can help prevent soil erosion effectively and rock gardens can improve drainage in your yard are only partly true. A raised rock mound genuinely lifts plant roots above wet subsoil, which is real and useful. A buried layer of gravel underneath a bed of soil does not improve drainage, it creates a perched water table, where water sits at the interface rather than moving through it. That is a well-known trap and it is the opposite of what people expect.

Dry creek beds

Dry creek beds are one of the best simple rock garden ideas for an Australian block, because they solve a drainage problem and look like a design decision. A convincing one has a defined profile with larger rock at the edges, graded stone through the middle, and a wandering line.

The legal limit: a dry creek bed managing overland flow within your own property is fine; one that collects and concentrates water at a boundary exposes you to a nuisance claim, because Australian case law is settled that you cannot concentrate and discharge water onto a neighbour’s land without an easement. Design it to slow and spread, not to aim.

Drainage, soil and the ground underneath

Good drainage is essential for rock garden plants to thrive, and it is the reason most rock garden failures are root rot rather than drought. The plants that suit this style are almost all adapted to sharp drainage, and Australian clay soils are the opposite.

There is no authoritative Australian rock garden soil mix specification, which is worth saying plainly rather than borrowing a British one. The principle: raise the planting area above the surrounding grade and build it from a free-draining mix coarse sandy loam with grit through it, not a rich garden mix that holds water. Depth beats recipe: 300mm of free-draining medium suits most rockery plants.

Two Australian conditions deserve specific attention.

Reactive clay. Across Melbourne, Adelaide and western Sydney, uneven soil moisture near a house is a footing problem, not a gardening one. CSIRO’s homeowner guidance asks for a paved apron around 900mm wide falling away from the building at about 1:60, and identifies garden watering near footings as among the most serious water problems a house faces. A loose gravel bed is not that apron. If your rock garden is going against the house on reactive clay, keep the falls away from the wall, keep irrigation off the footing zone, and remember the exposed slab edge requirement while you are there.

Site permeability. A gravel bed is generally treated as permeable under Victorian ResCode standards and counts toward a site’s soft landscaping percentage, but the classification varies by council. If you are replacing lawn with gravel on a block that is already close to its coverage limit, check before you order the stone.

The plants, and the tradition they came from

The classic rock garden is a European alpine garden sempervivum, saxifrage, alpine phlox, gentians, edelweiss, all adapted to short cool summers, snow cover and sharp mountain drainage. Almost every rock garden article online descends from that tradition. In Australia that garden is viable in Tasmania and the alpine areas of New South Wales and Victoria, and marginal to impossible elsewhere. Not a reason to avoid a rock garden, a reason to stop copying the plant list.

Cacti, and the biosecurity problem

The brief says cacti thrive in dry conditions, making them suitable for rock gardens. In Australia this needs a serious qualification, because several of the cacti that appear in rock garden photography are declared weeds here.

*Prickly pear (Opuntia species) is a Weed of National Significance. It must not be sold anywhere in New South Wales; Tasmania prohibits the importation, sale and distribution of opuntioid cacti; it is declared in South Australia, listed in the Northern Territory, and regionally prohibited or controlled across Victoria, where landholders have a legal duty to control wheel cactus. Hudson pear must not be imported into NSW, sold or offered for sale, and is a restricted invasive plant in Queensland. Harrisia cactus* is prohibited matter in Queensland you must not keep, move, give away or sell it, and sightings must be reported.

Golden barrel cactus is popular for rock gardens due to its low maintenance, and that one is legitimate, not a declared weed, sold here, genuinely undemanding. It wants full sun, sharp drainage and protection from prolonged wet, so it is far happier in Adelaide or Perth than in Brisbane humidity.

Three others worth naming because they appear constantly in rock garden inspiration and should not go into an Australian one: gazania, which must not be sold or traded anywhere in South Australia and is an environmental weed in Victoria, Queensland, Tasmania and New South Wales; *mother-of-millions (Bryophyllum delagoense), a restricted invasive plant in Queensland and a serious stock poison; and century plant (Agave americana), listed among the most invasive plants in south-eastern Queensland, with spines a Western Australian shire described as able to “pierce to the bone”*.

Succulents that do work here

Succulents are ideal for drought-tolerant rock gardens, and that holds with the sensible ones chosen. Blue chalk sticks (Senecio serpens, also sold as Curio repens) is a popular ground cover in rock gardens and is a good, well-behaved Australian choice: low, spreading, genuinely tough. Be precise about the species when you buy, because the Senecio genus also contains fireweed, a Weed of National Significance.

Agaves other than americana, aloes other than arborescens, echeverias, crassulas and portulacaria all earn their place. Native pigface (Carpobrotus glaucescens or C. rossii) is the Australian succulent groundcover and belongs here ahead of the South African sour fig, which is an environmental weed along the southern coast.

The Australian rock garden plant list

Organised by what each plant is for, rather than by botanical family.

Groundcovers to close the ground the weed control that improves with age. Creeping boobialla (Myoporum parvifolium), 0.15–0.3m × 1–2m. Eremophila glabra ‘Kalbarri Carpet’, a genuine weed suppressor for dry and Mediterranean climates. Grevillea ‘Poorinda Royal Mantle’ to cascade over rock. Cut-leaf daisy and yellow buttons for flowers. Native pigface for hot exposed positions. Native violet for the shaded side, because a rock garden is not always in full sun.

Strappy plants for structure. Lomandra longifolia Tanika® at 0.5–0.6m, Dianella revoluta ‘Little Rev’ at 0.3–0.4m, and Lomandra Great White™ or Dianella caerulea Little Jess™ where there is shade. These are the plants that stop a rockery looking like a car park.

Native grasses, which the brief rightly calls for. Kangaroo grass (Themeda triandra) at about 0.9m is the signature Australian rockery grass, and it feeds seed-eating birds and hosts butterflies. Poa and named Pennisetum selections work too buy named tissue-cultured cultivars rather than seed-grown fountain grass, which is weedy in parts of Victoria.

Shrubs for height. Westringia fruticosa Grey Box™ at 0.3–0.45m, dwarf banksias such as ‘Birthday Candles’, dwarf callistemons, and Correa ‘Dusky Bells’ for a winter-flowering plant that tolerates half shade and heavy frost.

On the entity list’s lavender: it will grow in an Australian rock garden given full sun and genuinely sharp drainage, and it is a reasonable inclusion in a Mediterranean-style planting. It is not low maintenance, it needs hard pruning annually or it goes woody and splits open.

On moss: outside cool, shaded, reliably moist parts of Tasmania and southern Victoria, moss in an Australian rock garden is a Northern Hemisphere fantasy. If you want that cushioned look, Scleranthus biflorus cushion bush is the Australian substitute, and it is a far better plant for the job.

Planting technique and spacing

Plant selection should be tailored to the local climate for successful gardening, which is the single most sensible line in the brief and the reason this section is organised by climate rather than by looks.

Build planting pockets rather than scattering plants across a gravel field: a genuine volume of free-draining soil, at least 300mm deep, between and behind the rocks where roots can run and where the rock will shade and cool the soil. That shading is why plants at the base of a rock often outperform the same plant three metres away.

Space for closure, not for photography. Work out each plant’s mature width and set them so the canopies will meet in two seasons. A groundcover at 1m spread goes in at roughly 800mm centres. This costs more plants up front and saves years of weeding.

Plant in autumn in most of Australia, so roots establish through the cool months before the first real summer. And rake the gravel back, plant into the soil, then rake it home around the stem, never plant into gravel that has been mixed through the soil.

Colour, texture and style

Rock gardens can be designed with contrasting colors and textures, and contrasting colors and textures enhance rock garden appeal true, and more useful stated as a rule of thumb: contrast the foliage, repeat the stone. Silver westringia against dark green correa, fine grass against a broad succulent rosette, a cascading grevillea spilling over a hard edge. Those patterns read at a distance in a way flower colour does not, and they hold their form year round, which matters in a garden built to look good in July as well as January.

Australian stone gives you earthy tones by default the sandstones, ironstones and granites in most yards sit in a narrow band of buff, ochre and grey. Using different colours of stone in one bed is where beginners lose the natural feel; one stone in different sizes is where the sense of geology comes from.

Zen-inspired rock gardens evoke tranquility and balance, and a Japanese karesansui has real beauty done properly, a few carefully placed large rocks in a field of raked gravel, where the empty space does the work. Two honest cautions for an Australian block. It is a high-maintenance garden disguised as a low-maintenance one: raked gravel shows every leaf, and in a garden with eucalypts nearby you will be raking weekly. And it is a style that fails badly when approximated, because with only three or four elements in the composition, each one has to be right.

Drought-tolerant plants are ideal for rock gardens in sunny spots, and rock gardens often use drought-tolerant plants for low maintenance both true, and both are really the same observation: a rock garden is a free-draining, high-light, reflected-heat environment, so the plants that are well suited to it are the ones adapted to exactly that. Choose for the conditions the rocks create, not for the picture.

Containers, paths and lighting

Not everything goes in the ground. Large pots holding a single agave or a clump of dianella extend a rock garden onto paving, and containers are how you do this style on a courtyard or over a slab. Group them in odd numbers too.

Gravel pathways through or beside the bed cost almost nothing, provided you use an angular stone that compacts rather than a rounded pebble that rolls and this is the one place where a geotextile separation layer is genuinely correct.

Low-voltage lighting transforms a rockery after dark, because raking light across stone reveals texture that flat daylight flattens. A plug-in 12V or 24V kit is legal for a homeowner to install; the weatherproof outdoor power point it plugs into is licensed electrician work. Uplight one or two feature rocks and a tree lighting everything kills the effect.

Wildlife, including the one nobody mentions

Rock gardens attract wildlife like birds and butterflies, and in Australia the list is better than that. A well-built rockery is genuinely good habitat for skinks and small lizards, for native bees nesting in crevices and bare ground, and for insect-eating and seed-eating birds where the planting includes grasses and small-flowered shrubs.

Then the part Australian rock garden articles almost never address. Rock piles are snake habitat cover, a thermal gradient, and a population of skinks and rodents to eat. The risk in a suburban garden is small and this is not a reason to avoid rockery. It is a reason to build one thoughtfully:

• Set large rocks so they bed down solidly rather than leaving voids and cavities underneath.
• Keep the rockery away from doors and paths where you walk in bare feet at dusk.
• Do not stack loose rock into deliberate cavity piles close to the house.
• Control rodents, because rodents are what actually brings snakes in.
• Keep the area around the rockery open enough to see the ground, and keep the surrounding lawns mown.

Handled that way, a rockery is one of the better things you can do for a suburban block’s lizard population, and the lizards are the point.

Heat, and the bushfire trade-off

A rock garden is thermal mass, and in Australia that cuts both ways.

Curtin University researchers measuring surface temperatures in Perth found grey pavers about 20°C above air temperature, asphalt 18–20°C above, mulch about 8°C, and lawn about 4°C. The caveat that matters: their rock sample was white, and it ran below ambient. Colour is doing almost all the work.

So the practical rule is not “rock is hot” or “rock is cool” it is that pale stone stays close to air temperature and dark stone does not. Blue metal and black pebble against north or west-facing walls will bake the greenery in front of them and radiate stored energy into the house at night the same trap as a paved courtyard, and the reason a rock garden replacing a lawn on a hot aspect can make a house measurably less comfortable. Pale river pebble or sandstone in the same position will not. If you are choosing purely on looks, at least choose the pale version of the look you want.

Against that, rock is where the bushfire advice lands firmly on one side. CSIRO’s bushfire guidance recommends “non-combustible materials (such as pebbles, shells, or gravel) as a mulch alternative”. The CFA notes that “most mulch used in gardens can also be a bushfire hazard as it will dry out and burn”, and applies its landscaping guidance to the first 10 metres around a house. The NSW RFS asks for “non flammable ground cover such as pebbles and crush tile” in asset protection zones.

If you are in a bushfire-prone area, a gravel bed against the house is genuinely recommended and bark mulch genuinely is not and the honest reading of the two bodies of evidence together is: use pale non-combustible ground cover near the house, and keep the dark aggregate for shaded areas away from windows.

One correction while we are here: AS 3959 does not require an asset protection zone. It sets construction requirements for the building based on bushfire attack level. APZ widths come from state planning instruments, not from that standard.

The maintenance claims, and one to ignore entirely

Rock gardens require minimal maintenance compared to traditional gardens, and rock gardens thrive on neglect and minimal watering once established. Both are partly true and both hinge on that last word.

The Australian establishment period is one to two years, with two the safer figure the Australian Plants Society’s guidance is that natives look after themselves “after two years”. Until then, the garden needs deep, regular watering, and a rock garden planted in November and left to fend for itself will simply die.

After establishment, the brief’s claim that drought-tolerant plants in rock gardens need watering every 2-3 weeks is not supported by any Australian source, and it is the wrong shape of advice. Australian horticulturists give the same answer consistently: deep, infrequent soakings judged by the weather rather than the calendar, two or three good soakings across the warm months for an established native rockery, and more in a heatwave.

The ongoing work is real but different: no mowing, very little watering, but leaf litter to clear, gravel to top up as it migrates, and hand weeding that gets slowly harder as organic matter builds in the stone. Sustainable Gardening Australia warns that dust and litter accumulating in crevices produces weeds that are “very difficult to remove” the argument for edges and litter removal restated.

And one claim to disregard completely. A well-designed rock garden can increase property value, there is no Australian valuation or agency data supporting this for rock gardens. Every figure in circulation (28%, 6–7%, 26%) traces back to American research from Clemson University, a US academic, and an international 2011 industry report, laundered through Australian real estate blogs. Build a rock garden because you want one, not as an investment.

What it costs

A realistic 20 square metre front yard rock garden, DIY, using Australian bulk prices:

Add a day’s mini excavator hire if the feature rocks are larger than you can handle, and a landscaper’s labour if you would rather not spend two weekends barrowing. The same job done entirely by a landscaper typically runs several times that, most of it labour.

Note what is not on that list: weed mat. The $60 it would have cost is the cheapest thing in the project and the most expensive mistake in it.

Balconies, and the limit of the idea

A rock garden can be created in small outdoor spaces like balconies with an important qualification, because rock is heavy and Australian balconies have structural limits.

A residential balcony is designed for a live load working out to roughly 200 kilograms per square metre. A 50mm gravel bed in a planter is about 80 kilograms per square metre, around 40% of the allowance, and generally fine. A single 500mm boulder concentrates roughly 785 kilograms per square metre over its footprint: nearly four times the allowance.

So: gravel and small stone in shallow planters on a balcony, yes. Feature boulders, no. And if the balcony is strata, attaching or building anything usually needs owners corporation approval, and there is a waterproofing membrane under that tiling which is expensive to breach.

Where to start

Mark the bed and check three things before you order anything: which way it falls, how much sun it actually gets across a day, and whether a truck can reach the drop point.

Then work in this order. Remove the existing lawn properly rather than smothering it, because the couch and kikuyu will simply come back through. Shape the ground and get the falls right. Build the soil up into free-draining mounds. Set the feature rocks, burying a third of each, bedding planes running the same way. Plant densely, at mature-width spacing, using the plant list for your climate rather than the alpine one. Install the edging. Then spread the gravel to a full 50mm, and rake it back around each plant rather than through the soil.

Water deeply for the first two summers. Blow the leaves out in autumn. Top up the stone when it thins. Trees can go in the same bed if there is room for the roots, small ones, well clear of walls and footings.

That is the whole method. It is simple, it is not quick, and the garden it produces has more life in it than a lawn ever did. The only genuinely irreversible decision in it is the one everybody makes first without thinking, which is the roll of black fabric that seems, for about eighteen months, like the smartest thing in the garden.