Boston fern (sword fern) Nephrolepis exaltata
Boston fern (sword fern) (Nephrolepis exaltata) is an evergreen perennial groundcover in the Nephrolepidaceae family, native to Tropical and subtropical America, including Florida and the Caribbean. It grows 40–90 cm (16–35 in) tall and 50 cm–1.2 m (20 in–3.9 ft) wide, wants shade and high water, and is hardy to about 5 °C (41 °F). Space plants about 50 cm (20 in) apart.
Plan Boston fern (sword fern) in your garden →
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Boston fern (sword fern) at a glance
| Type | Perennial groundcover, evergreen |
|---|---|
| Family | Nephrolepidaceae |
| Mature height | 40–90 cm (16–35 in) |
| Mature spread | 50 cm–1.2 m (20 in–3.9 ft) |
| Spacing | 50 cm (20 in) centre to centre |
| Sun | Shade, at least 1 h of direct sun a day |
| Water | High; drought tolerance none, waterlogging tolerance low |
| Soil pH | 5–6.5 |
| Cold hardiness | About 5 °C (41 °F) once established (roughly USDA zone 11) |
| Heat stress | Likely above about 32 °C (90 °F) |
| Wind tolerance | None |
| Pollinator value | None |
| Edible | Not grown as food |
| Native to | Tropical and subtropical America, including Florida and the Caribbean |
| Common in gardens of | 🇺🇸 United States, 🇬🇧 United Kingdom, 🇩🇪 Germany, 🇳🇱 Netherlands, 🇧🇷 Brazil, 🇲🇽 Mexico, 🇦🇺 Australia |
Is Boston fern (sword fern) toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not poisonous to cats or dogs (ASPCA).
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Boston fern (sword fern)
No well-documented helpful pairing. Group it with plants that like shade and high water.
Questions about Boston fern (sword fern)
- How far apart should I plant Boston fern (sword fern)?
- About 50 cm (20 in) apart, centre to centre. A mature plant spreads 50 cm–1.2 m (20 in–3.9 ft).
- Does Boston fern (sword fern) need full sun?
- Shade: at least 1 hours of direct sun a day.
- How much water does Boston fern (sword fern) need?
- High water. Drought tolerance is none and waterlogging tolerance low.
- How cold-hardy is Boston fern (sword fern)?
- It tolerates about 5 °C (41 °F) once established, roughly USDA zone 11.
- Is Boston fern (sword fern) poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Not poisonous to cats or dogs (ASPCA).
- What grows well with Boston fern (sword fern)?
- There is no well-documented companion pairing for Boston fern (sword fern). Group it with plants that like the same sun (shade) and water (high).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- UF/IFAS Extension tropical and subtropical fruit and landscape publications, University of Florida
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
Notes and assumptions
- A tropical plant: outdoors only in frost-free, humid climates; elsewhere a houseplant for bright, indirect light that likes warmth and humidity and hates cold draughts.
- Arching, sword-shaped fronds with many small leaflets, in hanging baskets on porches and in Victorian parlours. ‘Bostoniensis’ was found in 1894 in a shipment of plants to Boston and became the most popular fern in the world. Needs humidity; spreads by runners.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
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