Ponga (silver fern)
The tree fern behind New Zealand's silver fern emblem - the underside of each frond is a striking silvery white. Needs a sheltered, shaded or semi-shaded site with consistently moist, humus-rich soil; harsh sun or dry wind will scorch fronds. Can eventually reach 10m, though growth is slow. Marginal in the coldest inland/southern gardens due to frost sensitivity, so no Otago planting window is listed. Ferns don't flower - it's grown for foliage.
- Sun
- shade
- Water
- high
- Spacing
- 300cm
- Difficulty
- intermediate
- Grows in
- Whangārei / Northland, Auckland, Hamilton / Waikato, Tauranga / Bay of Plenty, Gisborne, Napier / Hawke's Bay, New Plymouth / Taranaki, Palmerston North / Manawatū-Whanganui, Wellington, Nelson, Tasman, Blenheim / Marlborough, West Coast, Christchurch / Canterbury
- Mature height
- 10m
- Evergreen
- Yes
When to plant by region
In Whangārei / Northland, Auckland, Tauranga / Bay of Plenty, Gisborne and Napier / Hawke's Bay: March-April and September-November. In Hamilton / Waikato, New Plymouth / Taranaki, Palmerston North / Manawatū-Whanganui, Wellington, Nelson, Tasman, Blenheim / Marlborough, West Coast and Christchurch / Canterbury: September-November.
Growing stages
Planting & establishmentFirst few months
- Choose a sheltered, shaded or semi-shaded site with consistently moist, humus-rich soil - harsh sun or dry wind will scorch fronds
- Water generously and keep soil consistently moist while establishing; this is a high-water species, not a dry-tolerant one
- Frost-tender when young, so protect in colder inland or southern gardens
Early growthFirst few years
- Growth is slow, so be patient as new fronds unfurl from the crown
- Keep checking that fronds aren't scorching in sun or wind, and add shade or shelter if they are
- Marginal in the coldest inland/southern gardens, which is why no Otago planting window is listed
Maturity
- Each frond's silvery-white underside is the feature the silver fern emblem is known for
- Can eventually reach 10m, though this takes many years given the slow growth rate
- As a fern it never flowers - it's grown purely for its foliage