Erect sword fern, also known as Boston fern (Nephrolepis exaltata), is a popular and attractive plant. It offers lush greenery, making it a favored choice for enhancing indoor or outdoor spaces due to its graceful appearance and adaptability.
Understanding Erect Sword Fern
The erect sword fern is an evergreen plant known for its upright, spreading growth habit. Its fronds are typically sword-shaped, displaying a rich green color and a pinnate arrangement. While the species Nephrolepis exaltata has erect fronds, popular cultivars like ‘Bostoniensis’ (Boston fern) are recognized for their gracefully arching fronds. This fern is native to humid forests across tropical regions, including northern South America, Mexico, Central America, Florida, the West Indies, Polynesia, and Africa.
Caring for Erect Sword Fern
Light
Erect sword ferns thrive in bright, indirect light, mimicking their natural environment beneath a forest canopy. Direct sunlight can scorch their delicate fronds, causing browning. Indoors, place them near a north or east-facing window for gentle, filtered light. For south or west-facing windows, position the plant a few feet away or use a sheer curtain to diffuse intense light.
Water
These ferns prefer consistently moist soil, though they are more tolerant of drought than many other fern varieties. Water thoroughly when the top layer of soil begins to dry, ensuring the potting medium remains evenly moist but not saturated. Reduce watering frequency during winter when the plant’s growth naturally slows.
Soil
Erect sword ferns flourish in well-draining soil rich in organic matter. A peaty, soil-based potting mix is recommended for indoor cultivation. For outdoor planting, incorporating compost or other organic material enhances soil fertility and drainage. An ideal soil pH for this fern ranges between 5.5 and 6.5.
Humidity and Temperature
High humidity is important for erect sword ferns. Low humidity can cause frond tips to brown and become crispy. To increase indoor humidity, mist the foliage regularly, place the plant on a pebble tray, or use a humidifier. They prefer temperatures between 60°F and 75°F (15.5°C to 24°C). Temperatures below 50°F (10°C) can harm the plant.
Fertilizing
During the active growing season (spring to early fall), apply a weak solution of balanced, water-soluble fertilizer monthly. Outdoor ferns often require minimal fertilization if the soil contains sufficient organic matter. For potted plants, a diluted slow-release all-purpose fertilizer once per year or compost can suffice.
Planting and Placement
When planting erect sword fern, choose a location with bright, indirect light, such as a north or east-facing spot indoors, or a shaded area outdoors. The planting hole should be approximately twice the size of the root ball. For container growing, select a pot with good drainage and a well-draining, organically rich potting mix. Repotting may be necessary annually for young plants to accommodate growth.
Propagating Erect Sword Fern
Erect sword ferns are commonly propagated through division, best performed in spring or early summer during their active growing period. To divide, carefully remove the plant from its pot and identify the rhizomes, which are underground stems. Each division should have at least two to three fronds and a healthy root system. Alternatively, ferns can be grown from spores found on the underside of mature fronds. Spore propagation is a more involved process.
Common Issues and Solutions
Browning fronds often indicate insufficient humidity, underwatering, or direct sunlight. Increase humidity, ensure consistent soil moisture, and relocate the plant to a shadier spot. Overwatering leads to root rot; allow soil to dry slightly between waterings and ensure good drainage. Pests like spider mites, aphids, and scale insects can also affect ferns, requiring manual removal, insecticidal soap, or horticultural oils. Yellowing leaves may signal a nutrient deficiency or overwatering, requiring adjustments to fertilizing or watering routines.