Osmunda regalis is a perennial deciduous fern that can reach 1-2m tall. It is native to North Africa, the Middle East, and Europe.
It is easily identified by its woody trunk-like base, and exceptionally large, airy, and prominently-veined fronds.
Royal Fern Classification
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Tracheophyta
- Class: Polypodiopsida
- Order: Osmundales
- Family: Osmundaceae
- Genus: Osmunda
- Species: Osmunda regalis
- Varieties: Osmunda regalis var. regalis, Osmunda regalis var. bransiliensis, Osmunda regalis var. panigrahiana
- Common Names: Royal Osmund Fern, Common Flowering Fern, King Fern, and Osmund Fern
Nativity and Distribution
Flowering Fern is native to Northern Africa, the Middle East, Asia, and Europe. It has also been introduced in other countries like New Zealand and North America, but it is a rare species to observe due to increased drainage of wetlands for purposes of agriculture.
Physical Characteristics
- Leaves: Large, airy fronds, typically 1-2m long
- Stems: Brown to copper, stout, short rhizomes
- Roots: Fibrous root system
Royal Fern is a perennial, deciduous fern that can grow 1-2m tall. It is easily identified by its woody trunk-like base, and exceptionally large, airy, and prominently-veined fronds.
Leaves are robust, bipinnate, heavily veined, typically 1-2 m but can grow up to 4m. Each frond divides into 5-9 pairs of about 30cm long with scattered hairs.
Each pinna has 7-13 pinnules (sterile leaflets) 2-6 cm long, which are oblong, lanceolate, and have a leathery feel. The fronds are reduced to a terminal blade tip with a dense cover of bead-like brown sporangia.
In their initial growth, younger fronds have brown fuzzy hairs that disappear as they mature, leaving a smoother surface on both sides.
Stems are stout, copper brown, ascending rhizomes that, over time, build up a woody, sometimes trunk-like base, covered with interwoven roots. The persistent, long-lived rhizome is sometimes partially below the soil or at soil level, and that’s where the fronds emerge from crowns or clumps.
Reproduction, Dispersal, and Life Cycle
- Life Cycle: Perennial
- Seeds: Produces spores
- Climate: Temperate and subtropical climates
- Dispersal: Wind
O. regalis is a perennial plant thriving in temperate to subtropical climates in its native range. Like all ferns, it reproduces by spores.
The sporangia are borne on fertile and densely clustered portions of the fronds. They are released in late spring through summer in many temperate regions. Since they are tiny and light, they are mostly dispersed by the wind.
When suitable conditions occur, the spores germinate into a sporophyte, which in turn produces the rhizomes, roots, and the first fronds. Over many years, the rhizome base thickens while the fronds die back or are killed by frost in winter.
The rhizome and rootstock survive the harsh conditions for many years. They not only give rise to new fronds every year, but can also vegetatively regenerate new shoots if broken and planted under the right conditions.
Since the fern prefers marshy, wet, or boggy soils and partial shade, it is commonly located along rivers and lakes and other riparian areas and woodland bogs.
Similar Plants
- Osmunda spectabilis
- Osmunda japonica
- Osmunda lancea
Uses
- It is an award-winning ornamental fern, valued for its imposing fronds in a variety of gardens.
- The fibrous roots are used in potting other epiphytic ornamentals such as orchids due to their ability to retain water and provide aeration.
- The young shoots are consumed as a vegetable in some cultures.
- The rhizome is used as traditional medicine for treating fevers, coughs, sore throats, bone fractures, and arthritis pain.
Impact on Farms and Environment
In agricultural areas, Osmunda regalis may be a concern where the farms are near wetlands. The fern can invade ditches and pond margins, interfering with shading and drainage. However, the spread is typically slow and can be handled before it becomes invasive.
Where it becomes abundant, the fern may outcompete native plant species in riparian lands, negatively impacting local biodiversity. It is listed as an environmental weed in New Zealand, for instance, because it is naturalized and has impacted native wetland ecosystems.
That said, O. regalis native populations are also steadily declining due to wetland drainings and rhizome overharvesting for medicinal and horticultural use. In North America, for instance, it is a rare observation, and this has been mainly attributed to increased drainage of wetlands for purposes of agriculture.
Control
- Mechanical control: Cutting before fronds become mature
- Chemical control: Herbicide spot treatments
Digging out the rhizome rootstock and the fronds can be effective for smaller infestations if done right. Ensure all rhizome material is extracted to prevent regeneration. Cutting off the spore-carrying fronds can also limit the spread.
For larger infestations, spot treatments of aquatic-safe herbicides such as diquat and specific triclopyr formulations are recommended. Apply during spring and summer as active growth occurs for maximum intake.
Ensure to follow all application instructions to prevent non-target area damage near waterbodies or other important ecosystems.
Lead Editor for Insight Weeds.