Introduction & Discovery

Doodia media, the Common Rasp Fern, is one of the most widely distributed and recognisable native ferns of eastern Australia and New Zealand, its name commemorating the rough sandpapery texture of the frond surface and the distinctively serrated-dentate margins of the pinnae that give the genus its characteristic appearance. Unlike the chain ferns of the genus Blechnum with their smooth-margined pinnae, the rasp ferns of Doodia bear sharply toothed leaflets that feel gritty to the touch owing to scattered siliceous deposits in the epidermal cells, a feature that serves as both a diagnostic character and a handy field identification trick for anyone exploring Australasian bushland. The genus Doodia was established by the English botanist Robert Brown in 1810, in his landmark Prodromus Florae Novae Hollandiae et Insulae Van-Diemen (Preliminary Flora of New Holland and Van Diemen's Land), based on Australian material he collected during the voyage of HMS Investigator under Matthew Flinders (1801 to 1805). The genus was named in honour of Samuel Doody, an English apothecary, botanist, and early curator of the Chelsea Physic Garden who had died a century earlier in 1706. Doodia media itself was described by Brown in the same 1810 work. Recent molecular phylogenetic work by Shepherd and Perrie (2011), Gasper, Salino, and collaborators (2016, 2017), and others has demonstrated that Doodia nests within the broader Blechnaceae in a position that is close to, or arguably within, the expanded Blechnum sensu lato, and some contemporary authors have proposed merging Doodia into Blechnum as Blechnum parrisiae and related combinations, while others retain Doodia as a natural segregate genus on the basis of distinct morphology and ecology. For horticultural and popular purposes the Doodia combinations remain standard. Ecologically the species is a significant understorey fern of Australian eucalypt forests and New Zealand lowland native bush, growing on a wide variety of soils and under a range of canopy conditions from moist rainforest edge to relatively exposed dry sclerophyll forest. The modest size, handsome architecture, pink-flushed new growth, and notable drought tolerance for a fern have established the species as a popular subject in Australian and New Zealand native plant gardens and a rewarding exotic introduction for cool maritime gardens in the Northern Hemisphere. It offers a useful reminder that the Blechnaceae includes not only the large chain ferns of Blechnum and Woodwardia but a diverse range of smaller, often more drought-tolerant and frost-hardy forms that extend the family's horticultural usefulness considerably.

Discovery & Naming

The Common Rasp Fern was first formally described by the Scottish botanist Robert Brown in 1810, in his landmark Prodromus Florae Novae Hollandiae et Insulae Van-Diemen (Preliminary Flora of New Holland and Van Diemen's Land). Brown, who is regarded as one of the greatest botanists of the nineteenth century and who later became the first Keeper of Botany at the British Museum, accompanied Matthew Flinders on the voyage of HMS Investigator (1801 to 1805) which produced the first comprehensive scientific survey of the Australian coast. During this voyage Brown collected an enormous quantity of Australian plant material including the fern that would become Doodia media, gathered primarily from sites in New South Wales and Tasmania. The Prodromus, published in 1810, was the first major flora of the Australian continent and established many of the fundamental generic concepts still used in Australian botany. Brown established the genus Doodia in the Prodromus, naming it in honour of Samuel Doody (1656 to 1706), an English apothecary and botanist who served as curator of the Chelsea Physic Garden and was a pioneer of English cryptogamic botany. The specific epithet media means middle, referring to the species' intermediate size between the smaller D. caudata and the larger D. aspera. Throughout the nineteenth century the species was extensively collected and studied by Australian and European botanists, with additional species of Doodia described from New Zealand, the subtropical Pacific, and other parts of the Australasian region. The early New Zealand flora by John Dallachy, Joseph Hooker, and subsequent workers treated the species under a variety of names before its modern circumscription was established. Molecular phylogenetic work by Shepherd and Perrie (2011), Gasper, Salino, Schuettpelz, and collaborators (2016 and 2017), and others has demonstrated that Doodia species nest within the expanded Blechnaceae in a position very close to Blechnum sensu stricto, and several authors have proposed merging Doodia into Blechnum; the combinations Blechnum parrisiae, B. neohollandicum and relatives represent these new names, though Doodia combinations remain in general horticultural use.

Native Range & Distribution Map

Distribution map showing the native range of Doodia media.

Biology & Frond Morphology

Doodia media belongs to the genus Doodia in the family Blechnaceae, producing evergreen, essentially monomorphic (unlike many blechnum relatives), once-pinnate fronds of modest size arising from a short-creeping rhizome, commonly 20 to 50 centimetres long and occasionally to 70 centimetres in optimal conditions. blades are narrowly lanceolate, firm and papery to subcoriaceous in texture, and mid to deep green when mature, with new croziers emerging a striking pink to coppery-red from anthocyanin pigments before maturing to green. pinnae are narrowly lanceolate to oblong, with the diagnostic serrated-dentate margin that gives the doodia rasp ferns their common name, an acuminate apex, and a sessile broadly attached base. the lowermost pinnae are often enlarged and reflexed rather than reduced as in blechnum, another distinguishing feature of the genus. stipes are dark brown to blackish at the base with brown linear scales. 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 Doodia media 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 Doodia media 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.

Common Mistakes to Avoid

Several recurring errors undermine cultivation of Doodia media. Planting in heavy alkaline clay without amendment causes chlorosis and stunted growth; the species prefers acidic to slightly acidic free-draining soil. Siting in hot exposed positions with dry summer conditions produces bleached scorched fronds and stunted crowns, particularly in Mediterranean-climate gardens; the species needs at least partial shade outside humid maritime climates. Overwatering and planting in waterlogged heavy soils causes crown rot, despite the species' requirement for consistent moisture; drainage is more important than maximal moisture retention. Attempting outdoor cultivation in zones colder than 8b typically results in rhizome loss after the first severe frost without substantial winter mulching; the species is warm-temperate in its cold tolerance. Expecting the substantial size and dramatic presence of large Blechnum relatives leads to disappointment; the species is modest in scale and suits intimate garden compositions rather than specimen roles. Using hard tap water repeatedly in container culture gradually raises substrate pH and produces chlorotic decline; switch to rainwater or mildly acidified water. Confusing the species with D. aspera is common and identification requires attention to frond size, pinna texture, and overall habit.

Seasonal Considerations

Spring (September to November in the Southern Hemisphere, March to May in the Northern) is the main growth flush, with new croziers emerging from the rhizome crown and unfurling over two to three weeks with the characteristic pink to coppery-red anthocyanin colour. Remove any winter-damaged fronds before new growth emerges, apply a spring topdressing of compost or balanced slow-release fertiliser, and renew mulch to 3 to 5 centimetres. Divide established clumps early in the season if division is planned for the year. Summer is the period of continued frond development and modest growth; maintain regular deep irrigation during dry weather, keep mulch topped up, and monitor for slug damage on any late-emerging fronds. Autumn brings a secondary growth flush in cool maritime climates as moisture returns; continue irrigation until seasonal rainfall resumes, and begin collecting mature spore for propagation. Winter requires modest attention in zones 9 and warmer, where the species is essentially evergreen; in zones 8 and colder apply mulch over the crown and accept cosmetic foliar damage. Container plants in cooler zones move indoors or into frost-free glasshouse through the coldest months. Avoid heavy foot traffic around the crown at any season.

Diseases & Pests

Common issues affecting Doodia media 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

Doodia media 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

Doodia media 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

Doodia media is widely distributed and abundant throughout its Australian and New Zealand native range, assessed as of Least Concern and Not Threatened in both countries. The species has benefited in some areas from anthropogenic disturbance creating suitable roadside and forest-edge habitat, though intensive land-clearance and urban development have reduced populations in parts of coastal New South Wales, southeast Queensland, and greater Auckland. The species is not listed on any international threat register. In Australia the principal conservation concern is the vulnerability of populations to Phytophthora cinnamomi dieback in affected forest systems; the pathogen is known to attack the species and has contributed to local population losses in parts of its range. Climate change projections suggest moderate potential range shifts at the northern dry margins of the distribution but core populations are likely to remain stable. The plant is not in international commercial trade from wild-collected material; nursery supply in Australia, New Zealand, and overseas is entirely from spore-raised or divided stock, typically from small-scale specialist producers and native-plant-focused commercial nurseries.

Collector Notes

For collectors building a Blechnaceae holding, Doodia media is an essential representative of the Australasian rasp-fern group and offers an attractive contrast to the larger chain ferns of Blechnum and Woodwardia. Wild-provenance material from various Australian and New Zealand localities represents ecologically and genetically distinct stocks worth documenting; New South Wales sandstone populations, Tasmanian populations, New Zealand North Island populations, and New Zealand South Island populations all represent potentially distinct lineages under modern molecular study. Several slight horticultural variants have been noted, including forms with more intensely coloured new growth, forms with variegated or creamy-margined fronds (occasional sports rather than established cultivars), and dwarf forms from exposed coastal sites, but no formal cultivars are widely recognised and the species is grown essentially in its wild form. Nursery stock in Australia is widely available from native-plant specialist nurseries including Growing Native Plants, Muchea Tree Farm, and various state-based providers; in New Zealand native plant nurseries such as Oratia Native Plant Nursery stock the species widely. In the UK and continental Europe a growing number of specialist fern nurseries offer Doodia species, and in North America Pacific Northwest suppliers such as Fancy Fronds Nursery and Far Reaches Farm have carried them. Notable mature plantings in accessible collections include the Royal Botanic Garden Sydney, Mount Annan Australian Botanic Garden, Auckland Botanic Gardens, Otari-Wilton's Bush in Wellington, and various UK gardens.

Ethnobotany & Cultural Significance

Doodia media has a modest ethnobotanical record in both its Australian and New Zealand ranges. Among Australian Aboriginal peoples of eastern and southeastern Australia the species has been reported as a minor food source, with young croziers occasionally consumed after cooking; however, ferns are not prominent in Australian Aboriginal ethnobotany compared with the extensive use of flowering plants. The rhizome has been reportedly used in some traditional remedies as an astringent, though documentation is sparse and specific uses are not well recorded. In New Zealand the Maori name pukupuku applies to this species and to several related New Zealand Doodia (now also treated as Blechnum parrisiae and relatives by some authors), and the plant has a minor place in traditional rongoa Maori. Young unfurling croziers may occasionally be collected as pikopiko alongside kiokio, though the smaller size and rougher texture make this a less substantial food source than the large Blechnum species. The fronds have been used as bedding material and as a component of rudimentary insulation in various rural contexts. European settlers in both Australia and New Zealand valued the species as a decorative element in collected native fern arrangements during the Victorian-era fern craze (pteridomania), which saw large numbers of Australasian ferns exported to British and European fern houses and private collections. The species continues to feature in contemporary Australian and New Zealand native plant horticulture as a staple of shade garden designs.

Frequently Asked Questions