Giant swordfern
Nephrolepis biserrata · Nephrolepidaceae
📷 Daderot · Public domain
The gardener's calendar
In autumn, ease off feeding and take the chance to clean up around giant swordfern and prepare for winter.
ID card
- Common name
- Forked sword fern
- Family
- Nephrolepidaceae
- Foliage
- Evergreen, light green to dark green
- Adult size
- 24 to 40 inches in height
- Growth rate
- Moderate to fast
- Hardiness
- Tropical plant, low frost tolerance (59-68 °F minimum)
- Origin
- Tropical and subtropical zones of South America and Asia
Expert tips
The key tip
Arrose régulièrement sans détremper : le substrat doit rester humide mais jamais gorgé d'eau. En intérieur, brumise le feuillage 2-3 fois par semaine car cette fougère réclame une hygrométrie constante (60% minimum), sinon les frondes brunissent progressivement des pointes.
The common mistake
La majorité des jardiniers la tuent par excès d'eau stagnante ou en la plaçant trop loin d'une source de lumière indirecte : elle jaunit, les frondes se dessèchent et se détachent facilement.
The pro's trick
Rempote tous les ans au printemps dans un mélange drainant (terreau + écorce + perlite) : cette fougère produit beaucoup de jeunes frondes et déteste l'encombrement racinaire. Un pot trop petit ralentit sa croissance bien plus que la plupart ne le pensent.
Seasonal watch
En hiver (chauffage intérieur), l'air devient très sec : augmente la brumisation et éloigne la plante des radiateurs ou sources de chaleur directe. Les araignées rouges colonisent rapidement le revers des frondes quand l'hygrométrie chute sous 50%.
Care
Regular watering
Keep the substrate moist but not waterlogged. Water 2 to 3 times per week depending on the season. This fern loves atmospheric humidity: mist the foliage regularly or place the pot on a bed of moist beads to recreate a tropical climate.
Light and positioning
Prefer indirect, filtered light away from direct rays that scorch the foliage. A north-facing window or a well-lit corner without direct sun works perfectly for it. It tolerates partial shade but growth will be slower.
Substrate and drainage
Use light, well-draining potting soil enriched with peat or coconut fiber to retain moisture. A fern-specific or general indoor plant mix ensures a good balance between water retention and root aeration.
Moderate fertilizing
Apply a balanced, diluted fertilizer every 15 days during the growing season (spring-summer). Reduce to once a month in fall-winter. Prefer a light application: this fern is not a heavy feeder and excess mineral salts damage the fronds.
Frond maintenance
Regularly remove yellow, dead, or damaged fronds at their base with clean scissors. This fern branches naturally; light trimming of the tips encourages a fuller shape. Avoid excessive handling of the foliage as it is delicate.
Pests and prevention
Watch for scale insects and spider mites, especially in dry indoor environments. Excess moisture can promote root rot or fungal spots. Ventilate regularly and avoid watering in the evening. Inspect new fronds weekly for early detection.
Did you know?
Nephrolepis biserrata is one of the rare ferns to form root tubers, a unique adaptation mechanism for storing water in humid tropical climates. This distinctive botanical characteristic, combined with its finely divided fronds, has made it a prized species among fern collectors since the nineteenth century, the golden age of Victorian "pteridophilia" in Europe.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
Add this plant to my garden →Plants from the same family
- Narrow swordfernNephrolepis cordifolia
- Boston swordfernNephrolepis exaltata
- SageSalvia officinalis
- BoxwoodBuxus sempervirens
- GrapevineVitis vinifera
- Pedunculate oakQuercus robur
Tips generated and checked by Viridia — adapt them to your local climate.