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Cyathea dealbata
silver fern
Cyathea dealbata
Cyathea dealbata, commonly known as the silver fern or ponga, is a species of medium-sized tree fern native to New Zealand. It's easily recognized by the silvery-white undersides of its fronds, which contrast with the dark green upper surfaces. The trunk is typically covered in old, decaying frond bases, giving it a rough texture. It is a significant cultural symbol for New Zealand.
CategoryDetails
Plant TypePerennial plant
Estimated Plant Lifespan50 years lifespan
Sun Requirements2-4 hours direct sunlight (Partial Shade)
Watering Requirements

Method: Keep the soil consistently moist but not waterlogged.

Frequency: Water regularly, especially during dry periods.

Notes: Avoid overhead watering, which can promote fungal diseases. Water at the base of the fern.

Humidity Requirements

Level: High

Maintenance: Mist the fronds regularly, especially in dry climates. Consider using a humidity tray or humidifier indoors.

Care InstructionsProvide shelter from strong winds. Remove dead or yellowing fronds to maintain a neat appearance and prevent the spread of diseases. Mulch around the base of the fern to retain moisture and suppress weeds.
Temperature Range

Min: 5°C

Max: 25°C

Alternative NamesCyathea tricolor, Alsophila tricolor, ponga, Polypodium dealbatum, Cyathea dealbata tricolor, Cyathea falciloba, Hemitelia falciloba, silver tree fern, punga
Blechnum novae-zelandiae
Kiokio
Blechnum novae-zelandiae
Kiokio ferns thrive in similar moist, shaded conditions as the silver fern, creating a layered, visually appealing planting scheme.
Astelia fragrans
Bush Flax
Astelia fragrans
Astelia fragrans complements the silver fern with its strappy leaves and adds textural contrast, while also preferring similar conditions.
Pinus radiata
Monterey pine
Pinus radiata

Pine trees are fast-growing and can quickly shade out the silver fern, depriving it of the dappled sunlight it prefers. They also compete for water and nutrients.

Scale insects

Scale insects can infest the fronds and stems, sucking sap and weakening the plant. Symptoms include yellowing leaves and a sticky substance called honeydew. Treat with insecticidal soap or horticultural oil.

Spider mites

Spider mites are tiny pests that can cause stippling and browning of the fronds. They thrive in dry conditions, so maintaining adequate humidity can help prevent them. Treat with insecticidal soap or horticultural oil.

Steps:

    • Collect spores from mature fronds.
    • Sow spores on a sterile, moist substrate such as sphagnum moss or a seed-starting mix.
    • Keep the substrate consistently moist and in a warm, humid environment.
    • Once the prothalli (the fern's pre-sporophyte stage) develop, transplant them to individual pots.
    • Gradually acclimate the young ferns to outdoor conditions.

Neem Oil

Effective for controlling scale insects and spider mites.

Liquid Kelp Fertilizer

Provides essential nutrients and promotes healthy growth.

Slow-release fertilizer

Provides nutrients and helps with the plants growth.