Boston Fern (Nephrolepis exaltata 'Bostoniensis')

About Boston Fern

Boston fern — known locally simply as "hanging fern" or "sword fern" — is arguably the most recognizable fern in the world, a fixture of Filipino verandas and carports where its lush, arching fronds cascade gracefully from hanging baskets in every neighborhood. The cultivar Nephrolepis exaltata 'Bostoniensis' belongs to the family Nephrolepidaceae and was selected for its uniquely graceful, drooping frond habit that distinguishes it from the stiffly upright wild sword fern species. While many houseplants have come and gone from fashion, the Boston fern has remained a constant in Filipino homes for generations — a testament to its perfect compatibility with Philippine growing conditions.

The secret to Boston fern's enduring popularity in the Philippines is simple: it thrives in exactly the conditions that Filipino outdoor living spaces provide. The high humidity (65-85%) of Philippine air, the bright but indirect light of covered verandas and patios, and the warm tropical temperatures create an ideal environment where Boston ferns grow with minimal intervention. Walk through any Filipino residential neighborhood and you will see Boston ferns hanging from every other porch, carport, and balcony — often enormous, magnificently full specimens that have been growing in the same basket for years, watered daily and otherwise left to flourish in the humid tropical air.

Visually, a healthy Boston fern is a masterpiece of natural architecture. The fronds emerge from a central crown, arching outward and downward in a graceful fountain-like silhouette that can reach 60-90 cm in spread. Each frond consists of dozens of small, rounded leaflets (pinnae) arranged along a central rachis, creating the feathery, soft texture that distinguishes ferns from all other plants. The bright emerald-green color of healthy fronds brings vibrant life to shaded spaces. A mature, well-maintained Boston fern in a large hanging basket creates an almost spherical ball of cascading greenery — one of the most dramatic single-plant displays achievable in tropical gardening.

Beyond aesthetics, Boston fern earned recognition in the NASA Clean Air Study as one of the top air-purifying houseplants — particularly effective at removing formaldehyde from indoor environments. Its high transpiration rate also makes it an excellent natural humidifier, releasing moisture into dry air-conditioned interiors. This combination of ornamental beauty, air-purifying function, pet safety, and perfect adaptation to Philippine conditions makes Boston fern an essential plant for any Filipino home or garden.

History & Discovery

The Boston fern's origin story is one of horticulture's most serendipitous discoveries. In 1894, a shipment of wild sword ferns (Nephrolepis exaltata) from Philadelphia arrived at a florist in Boston, Massachusetts. Among the stiff, upright specimens, one plant displayed a dramatically different growth habit — gracefully arching, drooping fronds that cascaded downward rather than standing erect. This single natural mutation was propagated, named 'Bostoniensis', and within years became the most popular fern in American horticulture. The Victorian era's obsession with ferns ("pteridomania") was already fading, but the Boston fern reignited interest with its superior ornamental form.

From America, the Boston fern spread rapidly throughout the tropics where it found conditions far superior to the heated parlors of Victorian homes. In the Philippines, the plant found a second home — the tropical humidity, warm temperatures, and outdoor living culture provided exactly what Boston ferns need. By the mid-20th century, Boston fern was firmly established as the default hanging plant of Filipino homes, available in every plant stall and hardware store for as little as fifty pesos. Its accessibility and ease of propagation through division made it a plant that neighbors shared freely — many Filipino Boston ferns descend from divisions passed between families over decades.

The wild ancestor of Boston fern, Nephrolepis exaltata, is native to tropical regions worldwide. More significantly for Philippine growers, the closely related species Nephrolepis biserrata (giant sword fern) is native to the Philippines and grows abundantly in the wild — on tree trunks, walls, fences, and rocky outcrops in humid, shaded environments throughout the archipelago. This native relative demonstrates that Nephrolepis ferns are fundamentally at home in Philippine conditions, and the cultivated Boston fern benefits from this same environmental compatibility.

How to Plant Boston Fern in the Philippines

Boston fern is one of the most affordable and widely available ornamental plants in the Philippines. Small to medium plants cost just ₱50-100 at plant stalls, hardware garden sections, weekend tiangge markets, and even sidewalk vendors. Larger, fuller hanging specimens run ₱100-200 — still remarkably affordable for the dramatic visual impact they provide. The plant's ease of propagation through division means that many Filipino plant owners receive their Boston fern as a gift or division from family and neighbors rather than purchasing it.

Planting Steps

1. Select a full, healthy specimen: Look for dense green fronds without brown tips or yellowing. The plant should feel heavy (indicating moist, healthy roots). Avoid plants with sparse, leggy fronds or visible pest damage. Smaller plants from divisions establish quickly; larger hanging specimens give instant gratification.
2. Choose the right container: Hanging baskets are the classic and best option — they showcase the cascading fronds and provide excellent drainage and air circulation. Coconut coir-lined wire baskets are ideal for Philippine conditions. Standard pots with drainage holes work for tabletop or shelf display. The container should be proportional to the plant's root mass — Boston ferns tolerate being slightly rootbound.
3. Use moisture-retentive, well-draining mix: Coco peat + perlite + compost (3:1:1) — more moisture-retentive than typical houseplant mixes because ferns need consistent dampness. Add chopped sphagnum moss for extra water retention in fast-drying hanging baskets. The mix should hold moisture evenly without becoming waterlogged or compacted.
4. Position in bright indirect light with humidity: The classic veranda, carport, or covered patio position. Hang from rafters or brackets where fronds can cascade freely with good air circulation. Avoid direct sun (scorches fronds). Indoor positions: near east-facing windows, bathrooms, kitchens, or any humid room with ambient light. The key requirement is HUMIDITY — Boston ferns struggle in dry, air-conditioned rooms without supplemental moisture.
5. Water immediately and establish a daily routine: After planting, water thoroughly until the entire root ball is saturated. For outdoor hanging baskets in Philippine heat, establish a daily watering routine — morning watering is ideal. The soil should never dry out completely. Mist fronds in dry conditions to maintain the humidity around the foliage.

Propagation

Division is the primary propagation method and is extremely simple: remove the plant from its container, use a sharp knife to divide the root ball into 2-4 sections (each with fronds and roots), and pot each section individually. Boston fern also produces runners (stolons) — thin, wiry stems that grow outward from the crown. These runners develop small plantlets that can be pinned to moist soil and severed once rooted. Division during the start of wet season (June) gives fastest recovery due to high humidity. One mature Boston fern easily produces 3-4 new plants through division — a perfect plant for sharing with neighbors and family.

Care Guide

Sunlight

Bright indirect light — the sweet spot for Boston fern. Dappled light through trees, the filtered light of covered patios and verandas, or positions near east-facing windows indoors provide ideal conditions. Early morning sun (before 9 AM) is tolerable and can enhance frond color, but direct midday or afternoon sun scorches fronds rapidly — causing bleaching, then browning. In too-dark positions (deep interior rooms with minimal light), growth becomes sparse and leggy, and the plant gradually declines. The ideal Filipino setup: hanging from the ceiling of a covered veranda where bright ambient sky light reaches the plant without direct sun beams.

Water

High — Boston fern is significantly more water-demanding than most houseplants. The soil should remain consistently moist (not waterlogged) at all times — think "wrung-out sponge" moisture level. In Philippine conditions: daily watering for outdoor hanging baskets during the hot dry season, every 1-2 days during wet season, every 2-3 days for indoor plants. Never let the root ball dry out completely — once dried, Boston fern root balls become hydrophobic (repel water). If this happens, submerge the entire pot in water for 15-30 minutes to rehydrate. Morning watering is best, allowing foliage to dry before evening.

Soil

Moisture-retentive but well-draining mix. Coco peat + perlite + compost (3:1:1) with optional sphagnum moss for extra water holding. The mix must retain moisture between waterings while draining well enough to prevent root rot from standing water. Avoid heavy garden soil. Boston ferns prefer slightly acidic conditions (pH 5.0-6.5). For hanging baskets that dry quickly, add extra coco peat or sphagnum moss to the mix. Repot or refresh soil annually as organic components break down and compact.

Humidity & Temperature

Humidity is the critical factor for Boston fern success — the plant needs 50-80% relative humidity, and this is exactly where the Philippines shines. Natural Philippine outdoor humidity (65-85%) provides perfect conditions, which is why veranda-hung Boston ferns thrive with minimal effort. Indoor challenges arise in air-conditioned rooms where humidity drops to 30-50% — causing the brown, crispy tips that are the #1 complaint of indoor fern growers. Solutions: mist daily, use pebble trays, group plants together, or place in naturally humid rooms (bathrooms, kitchens). Temperature: 15-30°C optimal. Philippine lowland temperatures are ideal year-round.

Fertilizer

Light feeder — ferns are sensitive to fertilizer and over-feeding causes more problems than under-feeding. Apply diluted liquid fertilizer (quarter to half strength balanced 20-20-20) every 2-4 weeks during active growth (wet season). Organic fish emulsion at half strength is gentle and effective. Slow-release granules at half the label rate, applied every 3-4 months, work for low-maintenance care. Signs of over-fertilization: brown frond tips, salt crust on soil surface, stunted new growth. When in doubt, use less.

Pruning

Regular grooming keeps Boston fern looking its best. Remove brown, dead, and yellowing fronds by cutting at the base — this redirects energy to healthy growth and improves air circulation within the dense crown. Trim runners (stolons) that extend beyond the desired shape unless you want to propagate from them. Once or twice a year, give the plant a thorough haircut if it becomes overly dense — thinning the interior fronds allows light and air to reach the crown center, promoting healthier new growth. Boston ferns are naturally "messy" plants that shed leaflets — sweep regularly beneath hanging specimens.

Growing Medium Options

Ornamental Uses

Boston fern's ornamental value lies in its cascading form — few other plants create such a dramatic waterfall of greenery from an elevated position. The soft, feathery texture and vivid emerald color bring a distinctly tropical, lush atmosphere to any space. As a hanging plant, it occupies vertical space that would otherwise be empty, making it ideal for small Filipino homes and apartments where floor space is limited.

Classic Filipino Positions

• Veranda and porch ceiling: The iconic Filipino display — rows of Boston ferns hanging from veranda rafters, creating a green curtain that softens architecture and provides a welcoming, natural atmosphere. Multiple specimens at varying heights create layered depth
• Carport and covered parking: Boston ferns hung from carport ceilings transform utilitarian spaces into garden-like environments. The shade and shelter of carports provide ideal growing conditions, and the plants soften the concrete and metal materials
• Balcony railing planters: For condo and apartment dwellers, Boston ferns in railing-mounted planters provide the cascading greenery of a garden on a small balcony. The fronds drape over the railing edge for dramatic effect
• Bathroom and indoor humidity zones: Placed on high shelves or hung from ceiling hooks in bathrooms, Boston ferns thrive in the humidity of showers and create a spa-like atmosphere

Design Applications

• Vertical garden element: Boston ferns fill the "cascading" layer in vertical garden compositions, complementing upright plants and trailing vines for full-coverage living walls
• Event and wedding decor: Large Boston ferns in decorative urns or hanging installations create instant lush greenery for outdoor Philippine events, receptions, and church decorations
• Shade garden accent: Planted in ground beds beneath trees, Boston ferns provide soft-textured ground cover in shaded areas where most ornamental plants struggle
• Restaurant and cafe ambiance: Hanging Boston ferns create the "garden dining" atmosphere popular in Filipino restaurants, particularly in al fresco and semi-outdoor dining areas

Air Quality & Oxygen

Boston fern holds a distinguished position in indoor air quality science — the NASA Clean Air Study (1989) ranked it among the most effective houseplants for removing formaldehyde from indoor air. Formaldehyde is one of the most pervasive indoor pollutants, continuously released by plywood, particleboard furniture, carpeting, glues, cleaning products, and even clothing. In Philippine homes and offices, new condo units with fresh cabinetry, newly purchased furniture, and recently painted walls are particularly high in formaldehyde levels.

Beyond formaldehyde removal, Boston fern excels at xylene and toluene absorption — pollutants from paints, varnishes, and vehicle exhaust. For Filipino homes near busy roads or in urban areas, this provides meaningful air quality improvement. Additionally, Boston fern's exceptionally high transpiration rate makes it one of the best natural humidifiers among houseplants. Each large Boston fern can release up to a liter of water into the air daily through transpiration, significantly boosting humidity in dry, air-conditioned Filipino offices and bedrooms. This natural humidification benefits human respiratory health, skin comfort, and even wooden furniture preservation.

Toxicity & Safety

Humans: Boston fern is completely non-toxic to humans. No part of the plant contains harmful compounds. It is safe for homes with small children who might touch or even mouth the fronds. The plant has no irritating sap, no sharp edges (fronds are soft and flexible), and no allergenic properties. This makes it one of the safest ornamental plants available — suitable for nurseries, schools, hospitals, and elderly care facilities without any toxicity concerns.

Pets: The ASPCA lists Boston fern as non-toxic to dogs and cats. This is a significant advantage over many popular hanging plants (pothos, philodendron, English ivy) which are toxic to pets. Cats are often attracted to the dangling fronds — while chewing may cause mild gastrointestinal upset from plant fiber, there is no toxic reaction. Boston fern is consistently recommended as a top pet-safe alternative for households with curious cats or dogs. The main concern is protecting the plant from pet damage rather than protecting pets from the plant.

Common Pests & Diseases in the Philippines

• Scale insects: Small brown bumps on frond stems (rachis) that suck sap, causing yellowing and weakening. The most common Boston fern pest in the Philippines. Remove with alcohol-soaked cotton swabs or spray with neem oil. Heavy infestations may require systemic insecticide. Inspect regularly during grooming sessions.
• Mealybugs: White, cottony masses in frond axils and on frond undersides. Sap-sucking pests that weaken the plant and excrete honeydew promoting sooty mold. Treat with neem oil spray, alcohol-dipped cotton swabs, or insecticidal soap. Good air circulation and regular inspection prevent major infestations.
• Slugs and snails: Particularly problematic for ground-level or low-hanging Boston ferns in Philippine gardens during wet season. They chew irregular holes in fronds. Use beer traps, copper barriers, or hand-pick at night. Hanging baskets at height avoid this pest entirely.
• Root rot (Pythium): Caused by waterlogged soil with poor drainage — less common in well-drained hanging baskets but problematic in dense, compacted potting mix. Symptoms: overall wilting despite moist soil, blackened mushy roots, foul odor. Prevention: well-draining mix, drainage holes, avoid compacted soil. Repot in fresh mix if detected early.
• Leaf tip burn (environmental): Not a disease but the most common aesthetic problem — brown, crispy frond tips caused by low humidity, direct sun exposure, over-fertilization, or water quality issues (high chlorine or salt). Trim affected tips, address the underlying cause. In most Philippine conditions, this is primarily an indoor air-conditioning problem.
• Fungal leaf spots: Brown or black spots on fronds during periods of high moisture with poor air circulation (overcrowded fronds, stagnant air). Improve air circulation by thinning dense growth, avoid overhead watering that keeps fronds wet for extended periods. Remove affected fronds.

Frequently Asked Questions

Sources

• Plants of the World Online — Nephrolepis exaltata. Royal Botanic Gardens, Kew.
• Wolverton, B.C. et al. (1989). Interior Landscape Plants for Indoor Air Pollution Abatement. NASA.
• ASPCA — Animal Poison Control Center: Toxic and Non-Toxic Plant Lists — Nephrolepis exaltata (Non-Toxic).
• Jones, D.L. (1987). Encyclopaedia of Ferns. Timber Press.
• Hoshizaki, B.J. & Moran, R.C. (2001). Fern Grower's Manual. Timber Press.

This guide is for informational purposes. Boston fern is non-toxic and safe for households with pets and children.