royal fernRoyal fern

Common name: Royal fern
Botanical name: Osmunda regalis
Management category: Advisory

Royal fern originates from Europe, west Asia, India, Africa and America. It’s deciduous (does back in winter) and is hard to miss with large fronds growing up to 3m long and 75cm wide. Naturalised in New Zealand by 1890, its fibres were used as a potting medium to cultivate orchids.

Why is it a pest?

  • It reproduces by spores which are dispersed by the wind, making it difficult to contain its spread.
  • It naturalises easily and quickly dominates its habitat, preventing native plants from growing.
  • Significant threat to wetland habitats due to its ability to produce spores for most of the year and distribute easily.
  • Can also spread via root fragmentation.

Where is it found?

  • Prefers wet, peaty habitats, drains and occasionally edges of freshwater margins.
  • Often found under grey willow and mānuka plants.
  • Has been found in isolated areas of western Bay of Plenty and Rotorua.

What does it look like?

  • It is quite a tall fern. It can grow to 2m in height and fronds can span out 3m.
  • Reddish brown spores appear in late spring to autumn.
  • Distinct yellow colour of foliage in autumn.
  • There are no flowers on this plant.
  • Leaves are hairless, except when young. They also turn red-brown in autumn.
  • Roots are black and extend quite deep into the ground.

What are the rules?


The Bay of Plenty Regional Council does not enforce the control of advisory species. It is landowner/occupier responsibility to manage these pests. Council may provide advice on how to manage or control these species if required.

How do you get rid of it?

Royal fern can be sprayed but care is needed when using agrichemicals over water.

If manually removing plants, always take care contain the spores and remove all fragments of the plant – including the roots which can grow quite deep. Dispose of plant material in general waste. If foliar spraying, leave the plants to rot down.

Always follow up every 3-6 months or when you notice new growth.


CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and directions for the purchase, use and storage of the product, are followed and adhered to.

Read more on pest control advice, information and regulations