The Rainfall Paradox: Wetter Summers, Drier Winters — and What It Means for Soil
Hong Kong’s climate is not what garden books think it is. The standard advice — “grow tropicals, they love humidity” — was written for a city that no longer exists. The summers are indeed wetter than ever: 2024 delivered 3,300 millimetres of rain, nearly 40% above the thirty-year average, and the typhoon season now reliably extends into November. But what nobody tells you is that the dry season is also getting drier. Between November and March, Hong Kong can go six weeks without measurable precipitation. The soil that was saturated in September is by January as hard as terracotta, and the plants that thrived in August’s steam-bath conditions are now dying of thirst — not because there’s no water, but because their roots have been trained to expect the wrong thing.
This is the central misunderstanding of subtropical gardening. It is not that Hong Kong is getting hotter — it is, but plants are more adaptable to temperature than we give them credit for. It is that the distribution of water has changed. We are moving toward a Mediterranean pattern: intense wet periods followed by prolonged dry periods, with the added complication of tropical humidity during the wet season that rots the crowns of drought-adapted species even as their roots sit in standing water. The solution is not to water more during the dry season, nor to install drainage for the wet season. The solution is to fundamentally rethink what we plant and how we plant it.
I learned this the expensive way. In 2019 I planted a garden in Sai Kung with the classic Hong Kong palette — heliconias, alocasias, ferns, flowering gingers. It looked magnificent for eight months. Then the dry season of 2019-2020 delivered forty-three consecutive days without rain. By day thirty, the heliconias had collapsed. By day forty, the alocasias had gone dormant so completely that I assumed they were dead. (They weren’t, but that’s its own problem: plants that die visibly are easier to manage than plants that fake their own death and then rot when the rains return.) The gingers survived but never flowered again that year. The only plants that looked genuinely happy were the ones I’d planted as architectural accents — a Dasylirion wheeleri from the Chihuahuan Desert, an Agave attenuata I’d bought on impulse at the flower market, and a clump of Westringia fruticosa that a friend had brought back from a nursery in Melbourne. They didn’t just survive the drought. They looked better during it than they had during the wet season.
That garden was my education. I have since replanted it entirely. It now contains exactly zero heliconias, zero alocasias, and only one ginger — a Curcuma that earns its place by going properly dormant in winter, disappearing entirely into the soil rather than presenting a rotting corpse for four months. The rest of the planting is a deliberate experiment in dry-garden principles for a subtropical climate: a garden designed to thrive on the rainfall pattern Hong Kong actually has, not the one garden centres wish it had.
Look South: What Australian Gardens Can Teach Hong Kong
The most useful reference point for the Hong Kong dry garden is not the Mediterranean, despite the climatic similarity. It is Australia. Specifically, the coastal regions of New South Wales and southern Queensland, which share Hong Kong’s pattern of summer-dominant rainfall followed by a pronounced winter dry season, combined with high humidity year-round. This is not a combination that occurs anywhere in Europe. The Mediterranean has dry summers and wet winters — the exact inverse of Hong Kong — which means that Mediterranean plants are evolutionarily programmed to be dormant during the dry season and actively growing during the wet season. Plant a lavender in Hong Kong and it will try to grow during the winter dry, exhaust itself, and then rot during the summer wet. The Australian flora, by contrast, evolved under a summer-rainfall regime and understands the assignment.
The Australian dry-garden palette has been refined over decades by designers working in climates that are functionally identical to Hong Kong’s. The work of landscape architect Fiona Brockhoff on the Mornington Peninsula, for instance, demonstrates how to use structural plants — Lomandra longifolia, Dianella caerulea, various Eremophila species — to create gardens that look lush and layered without requiring irrigation. Brockhoff’s gardens are instructive because she designs for a climate where summer rainfall is abundant but winter drought is severe, exactly the Hong Kong pattern. Her plant combinations — grasses that move in the wind, shrubs with silver foliage that reflects heat, groundcovers that knit together to suppress weeds and retain soil moisture — translate almost directly to a Sai Kung or Clear Water Bay hillside.
The genus Eremophila, commonly known as emu bush, deserves particular attention. These are shrubs of extraordinary drought tolerance — some species can survive on less than 200 millimetres of annual rainfall — but, critically, they are also adapted to summer rainfall. Unlike Mediterranean shrubs, they do not require a dry summer dormancy. Eremophila nivea, with its almost-white foliage and purple flowers, performs beautifully in Hong Kong if given sharp drainage and full sun. Eremophila glabra ‘Roseworthy’ is a groundcover form that spreads to a metre wide, smothers weeds, and produces red-orange tubular flowers that attract sunbirds. I have both growing on a south-facing slope in Sai Kung that received no supplementary water between October 2025 and March 2026 — a period of nearly six months. Neither plant showed any sign of stress. The E. nivea flowered in February.
Another Australian genus that has outperformed every expectation is Westringia, the coastal rosemary. Westringia fruticosa is a shrub of quiet competence: small grey-green leaves, white flowers with tiny purple spots, a naturally dense habit that requires almost no pruning. It looks like rosemary but tolerates humidity in a way that actual rosemary (Salvia rosmarinus) does not. I have lost three lavenders and two rosemaries in Hong Kong. I have never lost a Westringia. The cultivar ‘Smokie’ has variegated leaves that light up a shady corner; ‘Zena’ is a compact form suitable for containers; ‘Jervis Gem’ is the standard and still the best for hedging. All of them accept summer rainfall without complaint and shrug off winter drought with the equanimity of a plant that evolved on coastal cliffs.
The Mediterranean Palette: Plants That Laugh at Drought
Not all Mediterranean plants fail in Hong Kong. The ones that succeed share a specific trait: they come from regions with summer rainfall. The Mediterranean basin itself is a winter-rainfall zone, but the eastern Mediterranean — parts of Turkey, Lebanon, Israel — receives occasional summer thunderstorms, and the plants from these areas are worth investigating. Similarly, the Mediterranean-climate regions of South Africa (the Cape) and Chile receive some summer moisture, and their flora can be surprisingly adaptable.
The succulent Euphorbias are the stars of this category. Euphorbia characias subsp. wulfenii — the classic Mediterranean spurge with its chartreuse flower heads and blue-green foliage — has survived four Hong Kong summers in my garden, planted in pure gravel with a handful of compost. The trick is to cut it back hard after flowering in spring, removing the spent stems at the base, which prevents the crown rot that kills most Euphorbias in humid climates. The new growth emerges in autumn, just as the rains return, and the plant enters the dry season as a tight, drought-resistant rosette. Euphorbia myrsinites, the creeping spurge with silver-blue leaves arranged in spiralling patterns, has proven even tougher — it spreads across gravel like a living sculpture, its stems rooting where they touch the ground, forming a mat that suppresses weeds and requires absolutely nothing from the gardener except occasional admiration.
Phlomis is another Mediterranean genus that has surprised me. Phlomis fruticosa, Jerusalem sage, produces whorls of butter-yellow flowers above felted grey leaves in late spring, and its seedheads are architectural enough to leave standing through winter. Phlomis russeliana is more herbaceous, spreading by rhizomes to form a groundcover of large, heart-shaped leaves that stay green through the Hong Kong winter. Both species need full sun and sharp drainage — I plant them on mounds of crushed granite, essentially creating miniature scree gardens — and both have proven resistant to the fungal diseases that typically attack Mediterranean plants in humid summers. The key, as with the Euphorbias, is air circulation. These are not plants for a crowded border. Give them space, give them gravel, and they will repay you with years of drought-proof performance.
The South African contingent is smaller but significant. Agapanthus praecox, the ubiquitous blue lily of the Nile, is so common in Hong Kong parks that it’s easy to overlook, but its drought tolerance is genuinely remarkable. I have seen clumps of Agapanthus growing in unwatered roadside planters on the Peak, their leaves reduced to grey-green straps, pushing up flower stalks through compacted subsoil. The secret to Agapanthus in a dry garden is not to water it at all during the dry season — the plant will go semi-dormant, its leaves shrivelling slightly, and then explode into growth with the first summer rain. Overwatering during winter is the fastest route to a non-flowering Agapanthus. The white-flowered form, Agapanthus praecox subsp. orientalis ‘Albus’, is particularly elegant against dark foliage and deserves to be used more widely.
Hardscape First: Why Stone and Gravel Are Your New Best Friends
The most important principle of dry-garden design is also the most counter-intuitive for Hong Kong gardeners: spend your first budget on hardscape, not on plants. The soil, the drainage, the paths, the retaining walls — these are the infrastructure on which everything else depends, and skimping on them guarantees failure. I have seen too many gardens where the owner spent HK$50,000 on plants and HK$2,000 on soil, and then wondered why everything died.
Gravel is the dry garden’s secret weapon. A 50-millimetre depth of 10-20mm crushed granite — not the polished pebbles sold in bags at flower markets, which are decorative but functionally useless — does three things simultaneously. First, it acts as a mulch, suppressing weeds and reducing evaporation from the soil surface. Second, it provides thermal insulation, keeping the soil cooler during the day and warmer at night, which moderates the temperature swings that stress plant roots. Third, and most importantly, it creates a dry microclimate around the crown of each plant, preventing the collar rot that kills so many drought-adapted species in humid conditions. Mediterranean and Australian plants are adapted to having their crowns dry and their roots moist — exactly the opposite of what a tropical garden provides. A gravel mulch makes this possible.
The grade of gravel matters. Too fine (under 5mm) and it compacts into an impermeable layer that sheds water rather than letting it through. Too coarse (over 30mm) and it leaves gaps that weeds exploit. The sweet spot is 10-20mm angular gravel — the angularity is important, because rounded pebbles roll and shift, while angular stone locks together into a stable surface. In Hong Kong, the best source is the aggregate yards in Sheung Shui, where a tonne of crushed granite costs roughly HK$600 delivered. For a typical 50-square-metre garden, two tonnes will give you a 50mm depth with some left over for paths.
Paths deserve their own paragraph. In a dry garden, paths should be permeable — gravel, decomposed granite, or open-jointed stone set in sand. Impermeable paving creates runoff that starves the surrounding soil of moisture, and in Hong Kong’s intense rainstorms, it can channel water so aggressively that it erodes planting beds. A gravel path, by contrast, absorbs rainfall and releases it slowly into the adjacent soil, functioning as a linear infiltration trench. It also looks better: a dry garden on gravel, viewed from a gravel path, has a visual coherence that a dry garden surrounded by concrete paving can never achieve.
Retaining walls in Hong Kong are typically concrete, which is functional but thermally brutal — concrete absorbs heat during the day and radiates it at night, creating a microclimate that can be 5°C hotter than the surrounding air. A dry garden planted against a concrete retaining wall will cook. The solution is to face the wall with stone — either dry-stacked granite, which is expensive but permanent, or a gabion cage filled with rubble, which is cheap and surprisingly attractive when colonised by ferns and sedums. Both options create a cooler microclimate behind the stone and provide planting pockets for species like Echeveria elegans and Sedum mexicanum that thrive in vertical crevices.
The Soil Revolution: Building a Substrate That Drains Like Provence
Hong Kong’s native soil is decomposed granite — acidic, free-draining, and low in organic matter. In its natural state, it is actually an excellent base for a dry garden. The problem is that decades of gardening advice have trained Hong Kong gardeners to “improve” their soil by adding compost, peat moss, and organic mulches — materials that hold water, raise fertility, and create exactly the conditions that drought-adapted plants have evolved to avoid.
The dry-garden soil recipe is simple and counter-cultural: remove the organic matter, not add it. I start with the existing decomposed granite subsoil and amend it with 30% by volume of sharp sand (not builders’ sand, which contains salt, but horticultural grit or coarse river sand) and 20% of 5-10mm gravel. The goal is a substrate that a handful of water passes through in under three seconds — if it takes longer, add more grit. Organic matter should be no more than 5% of the total volume, and it should be well-rotted leaf mould rather than compost, which is typically too rich. The resulting soil looks alarmingly infertile. It is. That is the point.
Many drought-adapted plants have evolved in nutrient-poor soils and actually perform worse when overfed. Excess nitrogen produces soft, sappy growth that is more susceptible to pests and less tolerant of drought. Lavandula species in rich soil become leggy and short-lived. Rosmarinus in compost-enriched beds develops root rot. Australian Proteaceae — Banksia, Grevillea, Hakea — are particularly sensitive to phosphorus, and standard fertilisers will kill them faster than drought ever could. The dry garden is a low-fertility environment by design, and the plants that thrive in it have evolved to extract what they need from seemingly barren ground.
The other critical factor is pH. Decomposed granite is acidic, typically pH 5.0-5.5, which suits many Australian and South African plants but is too low for most Mediterranean species, which prefer pH 6.5-7.5. The solution is to incorporate crushed limestone or dolomite into the soil mix at a rate of approximately 2 kilograms per square metre for Mediterranean sections of the garden, while leaving the Australian and South African sections unlimed. This creates a mosaic of soil conditions that mirrors the geological diversity of the plants’ native ranges. It sounds fussy. It is fussy. But the difference in plant performance is immediately visible — a Cistus in limed soil will double in size compared to one in acidic soil, while a Banksia in limed soil will turn yellow and die within a season. The extra hour spent soil-testing and amending by zone pays for itself many times over.
Garden Profile: The Wong Chuk Hang Experiment — Three Years Without Irrigation
In 2022, landscape architect Thomas Leung — a Hong Kong-born designer who trained at the University of Sheffield’s department of landscape architecture and spent five years working for Dan Pearson Studio in London before returning home — took on a commission that nobody else wanted. The client was a tech entrepreneur who had purchased a 1,200-square-foot industrial rooftop in Wong Chuk Hang, the former factory district now colonised by galleries, coffee roasters, and creative agencies. The brief was straightforward: a garden that required no irrigation, no gardener, and no ongoing maintenance budget. “He literally said, ‘I want plants that will survive if I forget they exist,'” Leung recalls. “I said, ‘That’s the only kind of garden I’m interested in designing.'”
Leung’s solution was radical by Hong Kong standards. He removed the existing soil — 300 millimetres of waterlogged compost that had been installed by the building’s previous occupant — and replaced it with a custom substrate: 60% expanded shale (a lightweight, porous aggregate that retains moisture without becoming waterlogged), 30% coarse sand, and 10% composted pine bark. The total depth was only 250 millimetres — shallower than a standard raised bed — but the expanded shale’s water-holding capacity compensated for the reduced volume. “People overestimate how much soil plants need,” Leung says. “The constraint forces the plants to develop deeper, more efficient root systems. It’s the opposite of spoiling them.”
The planting was equally uncompromising. Leung selected exclusively from three genera: Agave, Yucca, and Dasylirion, with a ground layer of Sedum species and the Australian grass Lomandra longifolia ‘Tanika’. There are no flowers in the conventional sense — the colour comes from foliage: the blue-grey of Agave parryi, the golden variegation of Yucca gloriosa ‘Variegata’, the fine, hair-like filaments of Dasylirion longissimum. The effect is sculptural, almost alien, a landscape that looks equally at home against the backdrop of Wong Chuk Hang’s converted factory buildings as it would in the Chihuahuan Desert.
Three years later, the garden has never been irrigated. “I visited in March this year,” Leung told me, “and the client had genuinely forgotten the garden existed. He was using the rooftop for storage. The plants were all alive. The Lomandra had self-seeded into the gravel paths. The Sedums had covered every exposed surface. It looked better than when I’d planted it.” Leung’s experiment demonstrates a principle that should be more widely understood: a garden designed for its climate, planted in the right substrate, with species selected for the conditions rather than against them, does not need maintenance. It needs neglect.
A Plant List for the Hong Kong Dry Garden
The following is not a complete catalogue — that would require a book, and several have been written — but a starting palette of plants that I have personally grown in Hong Kong conditions and can vouch for. All have survived at least two complete annual cycles without supplementary irrigation once established. “Once established” is the operative phrase: all newly planted specimens require watering for the first three to six months while their roots extend into the surrounding soil. After that, they are on their own.
Structural evergreens: Agave attenuata (the spineless century plant, ubiquitous in Hong Kong but still underused as a design element), Agave parryi (smaller, more compact, with fierce terminal spines — keep it away from paths), Dasylirion wheeleri (the desert spoon, its narrow leaves tipped with frizzy filaments that catch the light), Yucca gloriosa ‘Variegata’ (a vertical accent with cream-edged leaves, tolerant of salt spray for coastal gardens), Dracaena draco (the dragon tree, slow-growing but eventually magnificent, needs zero water once established).
Shrubs and sub-shrubs: Westringia fruticosa and its cultivars (the workhorse of the Australian dry garden, as discussed above), Eremophila nivea (silver foliage, purple flowers, requires absolutely perfect drainage), Eremophila glabra ‘Roseworthy’ (groundcover form, red-orange flowers), Phlomis fruticosa (yellow flowers in spring, felted grey leaves year-round), Artemisia ‘Powis Castle’ (the best silver foliage plant for Hong Kong, surprisingly humidity-tolerant if given full sun and sharp drainage), Teucrium fruticans (silver-blue foliage, a Mediterranean shrub that has proven more humidity-tolerant than expected), Correa alba (Australian fuchsia, white star-shaped flowers in winter when little else is blooming).
Grasses and grass-like plants: Lomandra longifolia ‘Tanika’ (the finest of the Australian mat-rushes, evergreen, deep green, completely indestructible), Dianella caerulea ‘Cassa Blue’ (blue-grey strappy foliage, small blue flowers followed by purple berries, spreads gently), Festuca glauca (blue fescue, the classic Mediterranean grass — short-lived in Hong Kong but so cheap and fast-growing that it’s worth replanting every two years), Pennisetum setaceum ‘Rubrum’ (purple fountain grass, technically an annual but self-seeds reliably in Hong Kong gravel beds), Muhlenbergia capillaris (pink muhly grass, an American native that produces clouds of pink flower heads in autumn — surprisingly drought-tolerant given its delicate appearance).
Succulents and groundcovers: Sedum mexicanum (the best groundcover sedum for Hong Kong, lime-green foliage, tiny yellow flowers, spreads rapidly across gravel), Echeveria elegans (Mexican snowball, forms tight rosettes of silver-blue leaves, needs protection from heavy rain but thrives in the crevices of dry-stone walls), Senecio mandraliscae (blue chalk sticks, a South African succulent with finger-like leaves that form a dense silver-blue mat), Delosperma cooperi (hardy ice plant, magenta flowers in summer, a South African succulent that tolerates summer rainfall if drainage is sharp), Portulacaria afra (elephant bush, a South African succulent shrub that can reach two metres in a container and thrives on total neglect).
For winter interest (the dry season): Aloe striatula (hardy aloe, yellow-orange flower spikes in December-February, the most cold-tolerant Aloe species and the most reliable winter flower in a Hong Kong dry garden), Aloe arborescens (torch aloe, red-orange flowers in winter, forms a shrub to two metres, widely planted in Mediterranean gardens and equally at home on a Hong Kong hillside), Correa alba (as above — its winter flowering is a genuine gift in a season when most dry-garden plants are resting), Helleborus argutifolius (Corsican hellebore, pale green flowers from December to March, the only hellebore that reliably tolerates Hong Kong’s summer humidity).
Plants to avoid: Lavandula of all species (they will die within eighteen months in Hong Kong’s summer humidity; if you must have lavender, treat it as an annual and replace every autumn), Rosmarinus officinalis (rosemary, the classic Mediterranean shrub, rots in Hong Kong’s wet summers despite every effort at drainage), Cistus species (rock roses, beautiful in California, miserable in Hong Kong), Echinacea purpurea and most other North American prairie perennials (they need cold winter dormancy and will exhaust themselves in Hong Kong’s warm winters), any Banksia species (beautiful but exquisitely sensitive to phosphorus, and Hong Kong soils are almost universally too rich for them).
The Philosophy of Doing Less
The hardest lesson of the dry garden is also the most important one, and I have left it for last because it cannot be taught through plant lists or soil recipes. It is this: a dry garden requires you to do less, and most gardeners are constitutionally incapable of doing less. We want to water, to feed, to prune, to tidy, to “improve.” Every one of these impulses is destructive in the dry garden. The plants have evolved for neglect. They do not need your help. They need you to leave them alone.
I have a Westringia in my garden that I planted in 2020. It has never been watered, never been fed, never been pruned. It is now two metres across, perfectly dome-shaped, covered in white flowers every spring, and it is the most frequently complimented plant in the garden. Visitors ask me what my secret is. “I ignored it,” I say, and they think I’m being modest. I am not being modest. The secret is genuinely that I ignored it. The plant knew what to do. My only contribution was not interfering.
This is the dry garden’s gift and its challenge. It asks you to trust the plants, to design the conditions and then step back, to accept that a garden does not need to be managed in order to be beautiful. In a city of constant intervention — where buildings are pressure-washed weekly, where hedges are trimmed into geometric submission, where the very idea of a garden implies a gardener — the dry garden is a quiet act of rebellion. It says: some things are better when left alone. Hong Kong may not be ready for that message. But its climate is.
