Nephrolepis exaltata (L.) Schott

Frond Dimensions

The fronds of Nephrolepis exaltata are 50–250 centimetres (20–98 in) long and 6–15 centimetres (2.4–5.9 in) wide, with alternate pinnae (the small "leaflets" on either side of the midrib). Each individual pinna is 2–8 centimetres (0.79–3.15 in) long.

Pinnae Structure

Pinnae are generally deltoid, and a pinnate vein pattern is visible on these highly compound leaves. Pinnae edges are slightly serrate, and the fronds are linear to lanceolate and glandular.

Rachis and Leaflet Details

The rachis bears monochrome sprout shoots. Leaflets are entire, undivided, and oblong-lanceolate, reaching up to 4.8 inches (120 mm) long and up to 0.9 inches (23 mm) wide. They are spaced less than 1 centimetre (0.39 in) apart.

Reproductive Features

The sori are rounded, and the spores are warty and wrinkled.

Rhizome Structure

Nephrolepis exaltata forms a slender, tuberous underground rhizome.

Cultivar Frond Traits

The species produces erect fronds, but the cultivars Nephrolepis exaltata 'Bostoniensis' (Boston fern) and 'Teddy Junior' have gracefully arching fronds.

Boston Fern Naming Origin

This arching frond mutation was discovered in 1894, in a shipment of N. exaltata sent to Boston from Philadelphia. David Fairchild documented an alternative proposed origin for the name Boston fern: that the term came from Florida pioneer nurseryman John Soar, who sent the plants to a friend in Boston.

Native Distribution

This fern is common in humid forests and swamps, particularly in northern South America, Mexico, Central America, Florida, the West Indies, Polynesia, and Africa.

Habitat Preferences

N. exaltata grows well in moist, shady locations, and is found frequently in swamps and floodplains. It can grow both as a terrestrial plant and as an epiphyte, and grows epiphytically on Sabal palmetto.

Common Cultivation Use

Nephrolepis exaltata is a very popular houseplant, often grown in hanging baskets or similar settings. It is a perennial plant hardy in USDA plant hardiness zones 9–11.

Cold Tolerance

Although the fern may appear completely dead after periods of frost, it will re-emerge in the spring.

Soil and Drought Tolerance

In general, Boston fern grows well in damp, well-drained, nutrient-rich soil, and among common cultivated ferns, it is the most tolerant to drought.

Indoor Humidity Requirements

Boston fern is adapted to humid conditions, so when grown indoors as a houseplant, misting is necessary when relative humidity falls below around 80%.

Light Requirements

While the plant prefers partial or full shade when grown outdoors, it does not grow in full shade indoors, and responds best to bright filtered light.

Propagation Method

Named cultivars do not grow true from spores, so the plant is usually propagated by dividing rooted runners.

Pet Safety

This species is known to be non-toxic, so it is safe around pets.