Australian native epiphytes for vertical or wall gardens
In practice, most Australian natives are poor candidates for the modular cell systems that green walls use, because the conditions are often at odds with how most natives grow. Shallow substrate, restricted root volume and the constant swing between wet and dry is a challenging scenario for plants that are adapted for an in-ground, full-depth soil profile.
The most successful native vertical gardens are mounted epiphytes and rupicolous plants that evolved to grow on vertical surfaces without any soil at all.
There is however a group of Australian plants that evolved to grow vertically, but with no soil and no irrigation. Epiphytes attach to trees, rock faces and cliff edges, drawing moisture from the air and rain and feeding on whatever organic matter collects around their roots. Rupicolous plants, or rock-dwellers, grow in crevices and on bare stone with virtually no substrate. Mount these plants on timber, tree fern board or a wire panel and you are giving them conditions close to their natural environment. For most domestic walls, this is the more honest way to create a native vertical garden.
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Epiphyte vs rupicolous
An epiphyte is a plant that grows on another plant. It uses the host for physical support only, feeding on rainwater, airborne dust and the organic debris that collects around its roots. Staghorns, elkhorns and native orchids are epiphytes.
A rupicolous plant is one that grows on or among rocks. Some plants are both: Dendrobium speciosum grows equally on tree bark and sandstone ledges. Both types are adapted to the same underlying conditions: vertical or near-vertical surfaces, excellent drainage, exposure to air movement, no continuous soil moisture.
Elkhorn fern (Platycerium bifurcatum)
Easy to growLow water once established
Elkhorn fern (Platycerium bifurcatum) — shield fronds clasp the mounting surface and collect organic debris; fertile fronds extend outward in the characteristic antler form that gives the plant its name.
Elkhorn is the most widely available and most forgiving of the mounted epiphytes. It produces two distinct frond types: flat shield fronds that clasp the mounting surface, collect falling debris and slowly decompose into a natural compost layer that feeds the plant, and upright fertile fronds that extend outward in the antler form. The shield fronds are the reason elkhorns are self-sustaining on a mount — they actively gather their own nutrition from whatever falls on them. Over time a single plant produces offsets that spread across the mount. It handles frost to approximately −5°C, making it one of the most cold-tolerant epiphytes on this list. See the native ferns guide for more on growing ferns in Australian gardens.
Staghorn fern (Platycerium superbum)
Moderately difficultModerate water
Staghorn fern (Platycerium superbum) — larger and more dramatic than the elkhorn, with deeply forked fertile fronds that can reach a metre in length on a mature specimen.
Staghorn is the larger, more dramatic relative of the elkhorn and produces a considerably more imposing display on a wall. The fertile fronds are deeply forked and can reach a metre or more in length. It requires warmer conditions than the elkhorn and more humidity, making it a natural fit for sheltered courtyards and south or east-facing walls in frost-free climates. Staghorn does not produce offsets freely, so a mature mounted specimen is a slow-built investment. Note that Platycerium superbum is a protected species in QLD and NSW, so purchase only nursery-grown stock.
Bird's nest fern (Asplenium australasicum)
Easy to growModerate water
Bird's nest fern (Asplenium australasicum) — the rosette of broad, undivided fronds funnels water and organic matter toward the root mass; a distinctive architectural form for shaded walls.
Bird's nest fern is the most architectural of the epiphytic ferns. In nature, it grows in the forks and on the trunks of rainforest trees in subtropical and warm temperate areas of the east coast, where its rosette acts as a natural funnel, channelling rainfall and falling leaf litter toward the root mass. On a mounted panel or timber slab it performs the same function and is genuinely self-sustaining in a sheltered position with consistent humidity. It suits south and east-facing walls where direct sun does not reach it. Keep the root mass consistently moist but not wet; the frond rosette should never have water sitting in it for extended periods. This fern is also a strong candidate for indoor vertical gardens in bright indirect light.
Basket fern (Drynaria rigidula)
Moderately difficultModerate to regular water
Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons
Basket fern (Drynaria rigidula) — nest fronds at the base collect debris and build up a self-sustaining compost layer; the foliage fronds above are deeply divided and more upright than the platycerium genus.
Basket fern belongs in the same functional category as the staghorn and elkhorn (it produces two distinct frond types with the same division of labour) but it is an entirely different plant with a more upright, deeply divided foliage frond. The papery nest fronds clasp the mounting surface and collect organic debris; the foliage fronds above them are deeply lobed and can reach 60–80cm. It is a tropical to subtropical plant, suited to the warmer and more humid parts of QLD and northern NSW, and it handles a drier atmosphere provided the root zone stays moist. In a sheltered garden position in a frost-free subtropical climate it will grow vigorously on a mounted board or a tree trunk.
Rock felt fern (Pyrrosia rupestris)
Easy to growLow water once established
Steve Fitzgerald,CC BY-SA 4.0, via Wikimedia Commons
Rock felt fern (Pyrrosia rupestris) — creeping rhizomes spread across bark and rock faces, covering a surface in small, round, felted fronds; one of the most effective plants for colonising a mounted panel.
Rock felt fern is the most practical plant on this list for covering a surface. The creeping rhizomes spread steadily across bark, timber and rock, producing small, round, grey-green fronds covered in a fine felt of hairs. The felt reduces water loss, which gives the plant its unusual tolerance of dry periods for a fern. On a mounted timber panel it will colonise the entire surface over a few seasons, filling gaps between larger mounted plants and creating a continuous green coverage. It is widespread along the east coast and handles a range of light conditions from full shade to filtered morning sun.
Weeping spleenwort (Asplenium flaccidum)
Moderately difficultRegular water
Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons
Weeping spleenwort (Asplenium flaccidum) — pendulous fronds hang downward from the mounting point, creating a distinctly different form to the upright growth of other epiphytic ferns.
Weeping spleenwort is the only genuinely pendulous epiphytic fern on this list. The fronds hang downward from the mounting point which creates a waterfall effect on a wall. It is a cool temperate to subtropical plant from the east coast, found naturally hanging from rock faces, cliff overhangs and the trunks of large trees in sheltered, shaded gullies. On a wall it suits south-facing and deeply shaded positions where other plants struggle. Mount on cork bark or timber in a sheltered position; the fronds are relatively soft and will shred in exposed conditions.
Hoya (Hoya australis)
Easy to growLow water
Hoya australis — glossy, semi-succulent leaves and clusters of small, waxy white flowers through summer; an epiphytic climber that clings to bark and rock with the same ease as a wall or mounted panel.
Hoya australis grows along the east coast from southern NSW to northern QLD, climbing the trunks and branches of rainforest trees as an epiphyte and spreading across rock faces as a rupestral plant. The leaves are glossy and semi-succulent which gives this plant an unusual resilience in a domestic garden context. The flowers are small, waxy and white with a pink centre, produced in clusters through summer, and strongly fragrant at night. On a wall it will cling and climb across whatever surface it is given. It suits filtered light and tolerates part morning sun but will not perform in deep shade or full western exposure.
Pink rock orchid (Dendrobium kingianum)
Easy to growLow water with dry winter rest
Pink rock orchid (Dendrobium kingianum) — sprays of pink to deep mauve flowers through winter and spring on a compact plant that grows naturally on cliff faces, rock outcrops and rough tree bark.
Dendrobium kingianum is the most garden-accessible native orchid and one of the most rewarding mounted plants on this list. In its natural habitat along the east coast it grows on sandstone cliff faces, granite outcrops and the rough bark of large trees. The flowers are produced in sprays through winter and spring, ranging from pale pink to deep mauve. It is significantly more cold-tolerant than most orchids, handling frosts to approximately −3°C in a sheltered position, which extends its range into the cool temperate south-east. The native orchid guide covers the full range of mounted orchids in more detail.
Rock lily (Dendrobium speciosum)
Moderately difficultLow water with dry winter rest
Rock lily (Dendrobium speciosum) — cream to pale yellow flower spikes with up to 100 individual flowers on a mature specimen; one of the most spectacular flowering events produced by any mounted Australian native.
Dendrobium speciosum produces one of the most spectacular flowering displays of any mounted Australian native. The cream to pale yellow flower spikes appear in spring and on a mature plant carry up to 100 individual flowers each, with a fragrance that carries several metres. In nature it grows on sandstone outcrops, cliff faces and the rough bark of large trees. It is accustomed to drying out completely between rain events and sitting exposed to full sun on bare rock, which makes it one of the most genuinely drought-tolerant plants on this list. It is slow to establish and slow to flower from a young plant — three to five years to a first significant display — but long-lived and low-maintenance once it settles. See the native orchid guide for more detail on this species.
Tiger orchid (Cymbidium canaliculatum)
Easy to growLow water with dry winter rest
sunoochi from Sapporo, Hokkaido, Japan, CC BY 2.0, via Wikimedia Commons
Tiger orchid (Cymbidium canaliculatum) — sprays of dark-spotted, waxy flowers through spring on a tough, drought-tolerant orchid from the hollows of large inland trees; the most heat and drought resistant mounted orchid on this list.
Cymbidium canaliculatum is genuinely heat and drought tolerant, naturally occurring in the hollows and on the rough bark of large trees across inland and northern Australia where temperatures are extreme and rainfall unreliable. The flowers are waxy and distinctively marked, either cream or green with dark red-brown spots. The leaves are stiff, channelled and adapted to water conservation. On a mounted board in a hot, dry, sunny position it will outperform anything else on this list. See the native orchid guide for more on growing Australian orchids at home.
How to mount an epiphyte
What to mount them on
Tree fern is the best all-round mounting surface as it is lightweight, long-lasting and its rough, fissured surface gives roots immediate purchase. Untreated hardwood slabs (avoid pine, which rots quickly and may off-gas) are a reliable alternative. For a wall panel rather than individual mounts, galvanised wire mesh stapled to a timber frame provides a surface that roots can grip and air can circulate through freely. Avoid treated timber, painted surfaces and anything that retains moisture at the point of contact as constant dampness at the root attachment point promotes rot.
Mounted epiphytic orchids on a tree fern — the roots attach directly to the surface over several months, after which the tie can be removed.
method of attachment
The method is the same across all epiphytes and most rupicolous plants. Cut a small pad of sphagnum moss and press it against the mounting surface where the plant's roots will sit. Position the plant against the moss pad and secure it with horticultural wire, wrapping through and around the root mass and mount several times until it holds firmly. The plant should not move when the mount is lifted. Over several months the roots will attach themselves to the surface.
A small pad of sphagnum moss between the root mass and the mount retains just enough moisture to help the roots establish — keep it thin and allow it to dry between waterings.
placement and watering your wall
Hang the mount in a position that suits the plant's light requirements. Most of the plants below prefer filtered light or morning sun rather than full western exposure. Water by soaking the entire mount or running a hose or watering can from the top until thoroughly wet. Allow it to dry completely before the next watering. In a humid climate this may be once a week; in a dry inland climate more frequently through summer. The roots of epiphytes need air movement between watering cycles. Constant moisture kills them faster than drought.
A well-established mounted epiphyte requires almost no intervention — periodic soaking, occasional frond removal and a position that suits its light requirements.
Plants at a glance
| Plant | Type | Light | Climate |
|---|---|---|---|
| Elkhorn fern | Epiphyte — mounted | Filtered light to part shade | East coast; frost tolerant to −5°C |
| Staghorn fern | Epiphyte — mounted | Filtered light | Subtropical to warm temperate east coast; frost sensitive |
| Bird's nest fern | Epiphyte — mounted | Shade to filtered light | Subtropical to warm temperate east coast |
| Basket fern | Epiphyte — mounted | Filtered light to part sun | Tropical to subtropical QLD and northern NSW |
| Rock felt fern | Rupicolous epiphyte | Filtered light to full shade | East coast, widespread |
| Weeping spleenwort | Epiphyte — mounted | Full shade to filtered light | East coast, cool temperate to subtropical |
| Hoya australis | Epiphytic climber | Filtered light to part sun | East coast, subtropical to tropical |
| Pink rock orchid | Rupicolous epiphyte | Bright filtered to morning sun | East coast; frost tolerant to −3°C |
| Rock lily | Rupicolous epiphyte | Bright filtered to morning sun | East coast, subtropical to warm temperate |
| Tiger orchid | Rupicolous epiphyte | Full sun to bright filtered | Inland and northern Australia; heat and drought tolerant |
keep reading
A Guide to Australian Native Gardening
How to plan, plant and care for a thriving native garden, whatever your experience level.
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