What does it look like?
Royal fern is a deciduous fern that has large fronds up to 3m long and 75cm wide. The fronds are feather-like, subdivided twice, yellow-green and tough. It produces separate fertile fronds that are brown and resemble tiny bunches of grapes. A short woody trunk grows up to 1.5m high and plants die back to the woody trunk in winter. Royal fern produces spores (which are a fern's equivalent of seeds), which are readily spread by wind.
This species prefers wet, peaty habitats, roadside drains and occasionally clay banks next to rivers or streams. It often grows beneath manuka and grey willow. It is tolerant of frost, saturated ground, moderate shade, and poor soils.
Why is it a problem?
Royal fern can naturalise and form dense colonies in a range of wetland habitats, especially in disturbed areas and under the shade of willows or manuka. The plants displace other small native wetland plants.