Giant sword fern (Nephrolepis biserrata) is a fern found in tropical regions around the world. It prefers shady conditions and moist, well-drained soil. Giant sword fern can grow to about 1.4 m in height. The individual leaves take on a papery texture.
I. Appearance and Characteristics
Nephrolepis biserrata (giant sword fern, 长叶肾蕨) is a tropical fern, endemic to Florida, Mexico, the West Indies, Central America, South America, Africa, and southeast Asia.
Nephrolepis biserrata is a large, erect, spreading, evergreen fern forming beautiful mounds of long, narrow, arching fronds that can reach 8 ft. (240 cm). It creates a lush, tropical effect, its tall fronds quickly spreading from horizontal stolons.
It is found growing in moist hammocks and swamps. This tropical species is hardy in zones 10-11.
II. How to Grow and Care
Sunlight
When grown outdoors, macho ferns should be placed in a shady or partly shaded location. They are frequently grown in large planters under covered porches or in the shade of an outdoor patio. Avoid placing these ferns in spots that receive direct sunlight throughout the day, especially the intense afternoon sun, as the delicate fronds burn easily.
Indoors, macho ferns do best in medium to bright indirect light but also tolerate low-light locations. Use a sheer curtain to diffuse harsh sunlight and protect your macho fern from any direct sunlight in your home.
Temperature and Humidity
Macho ferns grow year-round in USDA zones 9 and 10. They enjoy warm, humid conditions. As other tropical ferns, macho ferns are not frost-tolerant and need to be moved indoors or grown as a houseplant in regions with cold winters.
Watering
Ensure that the soil around your macho fern stays consistently moist, but not wet. Macho ferns are not drought tolerant so the soil should never be allowed to dry out completely. When grown indoors, macho ferns may need to be watered once or twice a week depending on the temperature.
Soil
Macho ferns require moist but well-draining soil that is airy, rich in organic matter, and slightly acidic. These ferns are epiphytic, so avoiding heavy soil that will compact around the roots of the plant is extremely important. Consider that macho ferns are often found growing natively near wetlands and swamps when you are picking out the soil for your fern. A mixture of regular potting soil, peat moss or coco coir, perlite, and orchid bark is a good homemade soil mix for macho ferns.
Fertilizing
Young plants require frequent fertilization and should be fertilized with a balanced, all-purpose fertilizer once every six weeks throughout the spring and summer. Mature and established macho ferns don’t need to be fertilized as often, and do well with an application of balanced, all-purpose fertilizer once every six months.
Pruning
If your giant sword fern starts to exhibit old, discolored or sick leaves, it will require some pruning in order to maintain its best and healthiest form. This can often happen as new growth shades older leaves. Also, damaged leaves should be removed to keep the aesthetics and the overall health of the plant. Ideal time for trimming old leaves is during replanting, but if needed, it can be pruned in spring or summer. Always use clean, sharp tools.
When removing the leaves, do not cut the top of the plant and instead prune the side leaves. Remove them as close to the base as possible as to ensure the space for the new growth. Wilted leaves should be trimmed down roughly 5 cm toward the base. Wear garden gloves and disinfect your pruning tools between the cuts to minimize the risks of contamination.
Propagation
Healthy, mature macho ferns are best propagated by division in the spring. To divide a macho fern, take these simple steps:
- Dig up the plant to expose the rhizomes and roots.
- Choose a section of the rhizomes and separate them from the main plant. Depending on the rhizome system, you may need to use a sharp knife to cut through some of the rhizomes.
- Plant the divided clumps in separate containers or at the same depth as the original fern in other locations in your garden. Water thoroughly immediately after planting.
Potting and Repotting
If you are growing your macho fern in a pot or container, you should be prepared to repot this fern every year or two years depending on its growth rate. Macho ferns tolerate being moderately root-bound but appreciate regular repotting to provide them with extra space. Only move up one pot size every time that you repot your macho fern, and be careful not to break too many of the delicate roots during repotting.
Overwintering
Below USDA zone 9, the fern needs to be overwintered indoors. Any time you are bringing outdoor plants indoors apply a precautionary pest treatment to avoid bringing pests inside. If possible, it is also a good idea to quarantine the plant for at least one to two weeks in an isolated room so that if pests are present they do not spread to any of your other indoor plants.
The fern goes into dormancy during the winter. As it won’t actively grow, it will require less water. Adjust the watering frequency but make sure the soil never dries out.
Transplanting
The perfect time for transplanting giant sword fern is mid-spring to early summer or early winter to late winter, offering the ideal conditions for growth. Choose a well-draining and partially shaded location for giant sword fern. Ensure a gentle, firm touch when handling to prevent damage.
Pests and Diseases
Common Pests
Ferns grown outdoors are more likely to develop pests or diseases than ferns grown indoors, however, macho ferns are generally pest and disease-free plants. Keep an eye out for some common pests such as mealybugs, scale, aphids, and fern mites.3 Treat affected plants with rubbing alcohol or insecticide to clear up any infestations.
Common Problems
Macho ferns will let you know their state of health by the way their leaves look. Take note of the following signs.
Browning and Crispy Tips
If your plant’s frond tips are turning brown and crispy, it usually means the humidity level is too low for the fern. This is common for houseplants during the winter when humidity is low. Mist the plant or place it near a plant humidifier to boost humidity levels.
Yellowing Leaves
Your fern may be overwatered if it is showing yellowing leaves. Overwatered ferns tend to shed their leaves, as well.
Dropping Leaves
The macho fern is notorious for heavy leaf drop. This is normal but it requires constant clean-up. However, the fern may be dropping leaves due to inadequate light or watering.
III. Uses and Benefits
Giant sword fern grows well both outdoors and indoors. It makes a large accent groundcover and is excellent for natural landscapes and habitat restorations. This is a very tall fern, so best planted toward the back of a garden.
