Dicksonia herbertii (Skirted Tree Fern)
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Dicksonia herbertii
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Introduction & Discovery
Dicksonia herbertii, the Skirted Tree Fern, is one of the most visually distinctive tree ferns of the Australian rainforest, immediately recognisable by the dense petticoat-like skirt of persistent dead fronds that hangs beneath its living crown and clothes the upper trunk. This notable feature, shared to varying degrees by some other tree fern species but developed to an exceptional extent in D. herbertii, is not merely ornamental: it forms a humus-collecting basket that traps falling leaves, organic debris, and moisture, providing a supplementary nutrient and water source to the trunk's adventitious root system and creating a microhabitat for epiphytic ferns, orchids, mosses, and invertebrates. The species belongs to Dicksoniaceae, the ancient Gondwanan family of tree ferns distinguished by hairy rather than scaly stipe bases and by marginal sori enclosed in bivalved indusia. It is endemic to the subtropical and warm-temperate rainforests of eastern Australia, ranging from far north Queensland to northern New South Wales along the Great Dividing Range. The specific epithet herbertii honours Daniel Herbert, a nineteenth-century Australian botanical collector and pharmacist who contributed to the knowledge of Queensland's flora. In its native forests, D. herbertii is a conspicuous component of the mid-storey, rising on a stout trunk to heights of four to eight metres and spreading a broad crown of dark green bipinnate-pinnatifid fronds beneath the canopy of Argyrodendron, Flindersia, and other rainforest trees. In cultivation it is valued by fern enthusiasts in frost-free climates for its distinctive silhouette and ecological interest, though it remains less widely grown than the hardy southern-Australian Dicksonia antarctica.
Dicksonia is a genus of plants. Dicksonia is a genus of tree ferns in the order Cyatheales. It is regarded as related to Cyathea, but is considered to retain more primitive traits, dating back at least to the Jurassic and Cretaceous periods. The fossil record includes stems, pinnules, and spores.
Discovery & Naming
Dicksonia herbertii was described in the nineteenth century from material collected in the subtropical rainforests of Queensland. The specific epithet herbertii honours Daniel Herbert, a pharmacist and botanical collector active in Queensland during the mid-nineteenth century who contributed specimens of numerous plant species to botanical institutions. The genus Dicksonia was established by Charles Louis L'Heritier de Brutelle in 1789, honouring the Scottish nurseryman James Dickson. The species was initially known from the Wet Tropics of north Queensland and was subsequently documented from further south along the Great Dividing Range as botanical exploration of the eastern Australian rainforests intensified through the late nineteenth and twentieth centuries. Frederick Manson Bailey, the Colonial and then Government Botanist of Queensland, included the species in his comprehensive catalogues of Queensland flora. Taxonomic placement within Dicksoniaceae has been stable, and molecular phylogenetic analyses in the twenty-first century have confirmed the species' position within an Australasian Dicksonia clade alongside D. antarctica, D. fibrosa, D. squarrosa, and other regional species. The ecological significance of the dead frond skirt was documented by ecologists studying rainforest epiphyte communities in the late twentieth century, drawing attention to the species' role as a substrate provider in the subtropical rainforest ecosystem.
Native Range & Distribution Map
Distribution map showing the native range of Dicksonia herbertii.
Biology & Frond Morphology
Dicksonia herbertii belongs to the genus Dicksonia in the family Dicksoniaceae, producing evergreen, bipinnate-pinnatifid fronds forming a broad spreading crown above a conspicuous skirt of persistent dead fronds that hang vertically along the upper trunk. mature fronds are typically 2 to 3.5 metres long, broadly lanceolate in outline, dark green and somewhat glossy above with a paler underside. pinnae are alternate, lanceolate, and deeply pinnatifid with narrow oblong segments bearing finely serrate margins. stipes are stout, relatively short, dark brown, and densely clothed at the base with long, soft, dark brown to reddish-brown hairs characteristic of dicksoniaceae. the most distinctive feature of the species is the persistent dead fronds, which instead of falling away cleanly, bend downward and remain attached to the trunk for many years, forming a dense vertical skirt or petticoat that can extend one to two metres down the trunk. this skirt of dead fronds creates a humus-collecting basket that traps falling leaves, debris, and moisture, supporting a rich community of epiphytes and providing additional moisture and nutrients to the trunk via adventitious roots. fronds that unfurl from coiled fiddleheads (croziers). Like all ferns, it reproduces via spores borne on the underside of fertile fronds rather than flowers and seeds, and its life cycle alternates between a dominant sporophyte (the visible plant) and a small, short-lived gametophyte stage.
Reproduction & Propagation
Propagation of Dicksonia herbertii can be achieved through several methods:
- Spores: Collect ripe spores from the underside of fertile fronds, sow on sterilised peat or peat/perlite mix. Do not cover. Keep humid and in bright indirect light. Prothalli (gametophytes) typically develop in 4–12 weeks, and young sporophytes appear after a further 2–6 months.
- Division: Mature clumps with multiple crowns or creeping rhizomes can be divided in spring as new fronds emerge.
- Rhizome cuttings / offsets: Epiphytic genera (Davallia, Polypodium, Phlebodium) can be propagated from 5–10 cm rhizome segments with at least one frond and visible roots.
Cultivation & Substrate
Successful cultivation of Dicksonia herbertii depends on matching three conditions to its natural habitat: consistent moisture without waterlogging, a humus-rich yet well-drained substrate, and the correct light level for its frond type — whether dappled woodland shade, bright filtered light, or, for a handful of rock ferns, direct sun.
Substrate: A moisture-retentive, free-draining, organically rich mix is required. Target a blend of 35 percent composted bark fines, 25 percent well-rotted leaf mould or peat substitute, 20 percent loam, and 20 percent coarse perlite or pumice. The mix should hold moisture reliably while allowing excess water to drain, preventing the waterlogging that promotes root rot. Slightly acidic to neutral, pH 5.5 to 6.5. The species grows naturally on acidic basaltic and metamorphic soils in rainforest, and alkaline conditions above pH 7.0 cause chlorosis and poor growth. Incorporate acidic organic matter or elemental sulphur where native soil is alkaline. Good drainage is essential despite the high moisture requirement. Waterlogging promotes Phytophthora and Pythium root rot, which are difficult to treat once established. On heavy clay soils, plant on raised mounds or in raised beds with amended substrate. A gravel layer beneath the planting hole aids drainage on poorly-drained sites. Moderate. The species thrives in soils enriched by decomposing leaf litter and organic mulch, and supplementary feeding is rarely necessary in well-prepared organic soils. Young plants and those in containers benefit from a light spring application of slow-release balanced fertiliser at 20 to 30 grams per square metre. Avoid heavy nitrogen feeds that produce soft growth. Very high. The natural substrate is deep rainforest humus, and generous incorporation of composted bark, leaf mould, and well-rotted organic matter is essential. Annual mulching with 8 to 10 centimetres of organic material maintains soil structure, moisture retention, and nutrient supply. Allow leaf litter to accumulate naturally around the base and within the dead frond skirt.
Water: Rainwater (water the trunk!)
Light: Partial shade to deep shade in its native rainforest habitat, where the species grows beneath a dense canopy of subtropical and warm-temperate rainforest trees. The canopy typically filters 70 to 90 percent of direct sunlight, and the species performs best under similar conditions in cultivation. Dappled light or the shade of a high canopy produces the best crown development and deepest frond colour. Direct afternoon sun in warm climates causes rapid frond scorch and discolouration, and even morning sun can be damaging during hot summers. In cooler maritime climates where the species is occasionally grown, slightly more light can be tolerated, particularly in overcast conditions. Young plants are more shade-tolerant than mature specimens and establish best in deep shade before gradually receiving more light as the canopy develops. In glasshouse cultivation, shading equivalent to 60 to 80 percent reduction of direct light is appropriate.
Humidity: 70-95%
Common Mistakes to Avoid
The most common error specific to Dicksonia herbertii is removing the dead frond skirt for aesthetic reasons. The skirt is a functional feature that traps humus, retains moisture, and supports epiphytic communities; removing it exposes the trunk to desiccation and removes a significant moisture reservoir. Treating the species as equivalent to Dicksonia antarctica in terms of frost tolerance is another frequent mistake; D. herbertii is significantly less cold-hardy and requires frost-free or nearly frost-free conditions. Planting in insufficient shade, particularly in climates warmer than its native range, causes frond scorch and crown stress. Allowing the soil and trunk to dry out during establishment or dry weather leads to frond dieback and slow recovery. Overwatering to the point of waterlogging, as opposed to maintaining even moisture, promotes root rot. In temperate climates, failing to provide adequate winter protection in marginal zones results in crown loss. Attempting to grow the species in low-humidity conditions without supplementary misting is a common failure, as the species demands consistently high atmospheric moisture.
Seasonal Considerations
Spring (September to November): new croziers emerge and unfurl. Remove any winter-damaged fronds before new growth starts. Apply a spring topdressing of compost or slow-release fertiliser. Increase watering frequency as temperatures rise. Mulch renewal. Summer (December to February): peak growth and maximum water demand. Water deeply two to three times per week, supplementing with overhead misting during hot dry periods. Maintain shade. Monitor for pest activity. This is the period for spore collection from mature sori. Autumn (March to May): growth slows. Reduce watering frequency as temperatures cool but do not allow the trunk or dead frond skirt to dry out. Apply thick mulch layer in preparation for winter. In frost-prone areas, prepare winter protection materials. Winter (June to August): minimal growth. In frost-free climates, maintain basic moisture and monitor for winter dryness. In marginal areas, wrap the crown and upper trunk with fleece during cold spells below 2 degrees Celsius. Do not remove the dead frond skirt at any season.
Diseases & Pests
Common issues affecting Dicksonia herbertii in cultivation:
- Root/rhizome rot: Caused by waterlogged substrate, compacted soil, or overwatering in cool weather. Ensure the growing medium is well-aerated and never let pots sit in standing water for prolonged periods.
- Fungal leaf spot & Botrytis: Brown or grey blotches appear in stagnant, overly humid conditions. Improve air circulation, remove affected fronds, and avoid wetting foliage late in the day.
- Scale insects & mealybugs: The most common fern pests, hiding on stipes and frond undersides. Wipe off with a cotton swab dipped in diluted isopropyl alcohol, or treat with horticultural soap. Many chemical pesticides scorch fern fronds — always test on one frond first.
- Spider mites: Fine webbing and stippled fronds, common in dry indoor air. Raise humidity and rinse fronds regularly with tepid water.
- Frond browning (tip burn): Caused by dry air, direct hot sun, fluoridated or chlorinated tap water (especially in Nephrolepis, Calathea-loving filmy ferns), or soluble-salt build-up from fertiliser. Flush the pot with rainwater and reduce feeding.
Indoor Growing & Terrariums
Dicksonia herbertii can be grown indoors as a houseplant or terrarium subject when its humidity and light requirements are met.
Indoor Setup
- Light: Bright indirect light — an east- or north-facing window, or 30–60 cm under an LED grow light (10–12 hours/day). Most ferns scorch in direct midday sun.
- Humidity: 50–80%. Group plants, stand pots on a pebble-and-water tray, or run a humidifier; misting alone rarely raises ambient humidity enough.
- Temperature: 16–24°C (60–75°F) for most indoor species; avoid cold drafts and hot radiators.
- Substrate: Peat-free potting mix with added perlite and orchid bark for drainage; epiphytic genera (Platycerium, Davallia) grow best mounted on bark or in a bark-heavy orchid mix.
- Water: Keep consistently moist but never waterlogged. Let the top 1–2 cm of substrate dry slightly between waterings in winter.
- Air circulation: A gentle fan discourages fungal leaf spot without drying out the fronds.
Landscape & Garden Use
Dicksonia herbertii can be used in the garden wherever its hardiness and habitat preferences are matched. Ferns are classic choices for shaded borders, woodland gardens, stumperies, rockeries, stream-side plantings, and ground-cover under trees.
Landscape Tips
- Companions: Hostas, Astilbe, Heuchera, Tiarella, Epimedium, hellebores, snowdrops and other shade-tolerant perennials are classic partners.
- Soil preparation: Incorporate leaf mould or composted bark to improve moisture retention and mimic a forest floor.
- Mulching: A 3–5 cm mulch of chipped bark or leaf litter protects the rhizomes, conserves moisture, and slowly releases nutrients.
- Watering: Establish new plantings with regular deep watering during the first growing season; most hardy ferns need only occasional supplemental irrigation once established.
Conservation & Collector Notes
Dicksonia herbertii is not currently listed as threatened at national or state level in Australia and is classified as Least Concern under Queensland and New South Wales nature conservation legislation. The species has a broad range along the Great Dividing Range and is well represented in national parks and other protected areas throughout its distribution. It is not listed on the IUCN Red List and is not included in CITES appendices. However, the species is dependent on intact rainforest habitat, and historical clearing of lowland and foothill rainforest in eastern Australia has reduced its total range, particularly at lower elevations. Remaining populations in protected areas are generally secure, but edge effects from adjacent land clearing, altered fire regimes, and invasive species can degrade habitat quality. Climate change poses a long-term threat through potential reductions in rainfall, increased fire frequency, and upward shifts in the cloud base that could reduce the moist microclimate the species requires. The species is not commercially harvested at a significant scale, and nursery supply is primarily from spore-raised or small-scale trunk salvage operations. Ongoing habitat protection within the rainforest national parks of Queensland and New South Wales is the principal conservation measure.
Collector Notes
Dicksonia herbertii is a prized species in Australian native plant collections and in specialist tree fern collections worldwide, valued for its distinctive dead frond skirt and subtropical rainforest character. The species is available from specialist native plant nurseries in eastern Australia and occasionally from fern nurseries in the United Kingdom and Europe, where it commands premium prices due to its rarity in cultivation. Wild-provenance material from different parts of the range shows some variation in skirt density and frond size, with populations from higher elevations in the Border Ranges generally more compact and potentially more cold-tolerant. Notable specimens in public collections include plantings at the Royal Botanic Gardens Sydney, Brisbane Botanic Gardens Mount Coot-tha, and several private collections in the Blue Mountains and Sunshine Coast regions. In the United Kingdom, the species is grown in the Temperate House at Kew and in a few private collections in the far southwest. Collectors should source material from reputable nurseries and avoid wild-collected trunk sections unless from legitimate salvage operations with appropriate permits under state and federal environmental legislation.
Ethnobotany & Cultural Significance
The ethnobotanical record for Dicksonia herbertii in relation to Aboriginal Australian use is limited in the published literature, as the rainforests of eastern Australia were utilised by numerous Aboriginal groups whose specific plant-use knowledge is not always fully documented for individual fern species. Tree ferns in general were known to Aboriginal peoples of the rainforest regions, and the starchy pith of tree fern trunks was consumed as a food source after processing in some communities. The young unfurling croziers of various tree fern species were also eaten after cooking. Whether D. herbertii was specifically targeted or preferred over co-occurring species such as Cyathea and Dicksonia antarctica is not well documented. European settlers in Queensland and New South Wales used tree fern trunks, including those of D. herbertii, as a rough building material for huts, fences, and garden walls, continuing a practice borrowed from Maori and Polynesian traditions. In modern Australian horticulture, the species is valued primarily as an ornamental and is grown in specialist native plant and fern nurseries. The dead frond skirt is sometimes promoted as a feature for growing epiphytic orchids and ferns, adding to the species' horticultural interest.
Frequently Asked Questions
Why does Dicksonia herbertii retain its dead fronds?
The persistent dead frond skirt is a functional adaptation that creates a humus-collecting basket around the upper trunk. Falling leaves, organic debris, and moisture are trapped within the skirt, creating a supplementary nutrient and moisture source for the adventitious roots growing through the trunk mantle. The skirt also supports a community of epiphytic ferns, mosses, and invertebrates that contribute to the nutrient cycling around the plant.
Should I remove the dead frond skirt for a neater appearance?
No. The dead frond skirt is a functional feature and removing it reduces the plant's access to supplementary moisture and nutrients, exposes the trunk to desiccation, and eliminates a significant ecological microhabitat. If individual dead fronds become unsightly, they can be trimmed to a uniform length rather than removed entirely, but the general practice should be to leave the skirt intact.
Is Dicksonia herbertii as hardy as Dicksonia antarctica?
No. Dicksonia herbertii is significantly less frost-tolerant than D. antarctica, surviving only brief frosts to approximately minus 2 to minus 4 degrees Celsius compared with minus 5 to minus 7 degrees Celsius for D. antarctica. It requires a frost-free or nearly frost-free subtropical to warm-temperate climate for reliable outdoor cultivation.
Can I grow Dicksonia herbertii in a temperate garden?
Only in the mildest maritime climates with rare or absent frost. In the United Kingdom, the far southwest of Cornwall, the Isles of Scilly, and sheltered coastal gardens in southern Ireland offer the best chances. In most temperate gardens, a heated conservatory or glasshouse with minimum winter temperatures above 8 degrees Celsius and high humidity is required.
What is the growth rate of Dicksonia herbertii?
Trunk growth is slow, typically 3 to 6 centimetres per year in good conditions. Spore-raised plants take ten or more years to develop a visible trunk. Frond production is steady, with a healthy plant producing five to ten new fronds per year. The dead frond skirt develops gradually as fronds die and persist, taking several years to form a substantial petticoat.
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Quick Reference Summary: Dicksonia herbertii
Golden Rule: Match moisture, light and humidity to each fern’s natural habitat — woodland ferns need shade and humus, rock ferns need drainage, filmy ferns need constant humidity.
Dicksonia herbertii, the Skirted Tree Fern, is a distinctive species of the subtropical and warm-temperate rainforests of eastern Australia, recognised by its dense skirt of persistent dead fronds that forms a humus-collecting basket around the upper trunk. Native to Queensland and northern New South Wales along the Great Dividing Range, it grows in deep shade in high-rainfall forest at elevations of 400 to 1,200 metres. The species produces a broad crown of dark green bipinnate-pinnatifid fronds atop a trunk reaching 4 to 8 metres. Hardy to USDA zones 9b to 11, it is less frost-tolerant than Dicksonia antarctica and requires frost-free to near-frost-free conditions with high humidity and consistent moisture. The dead frond skirt should not be removed, as it serves important moisture-trapping and ecological functions. Propagation is primarily by spore. A prized species for subtropical rainforest-style gardens and specialist tree fern collections.