Button fern is a compact, low-maintenance type of fern native to Australia and New Zealand. This plant is known for its compact size and arcing fronds lined with small, rounded pinnules. It’s commonly kept as a houseplant in temperate climates and prefers part shade, moist soil, and moderate humidity.
I. Appearance and Characteristics
Pellaea rotundifolia, the button fern, is a species of fern endemic to New Zealand, where it grows in scrub and forests. It is also a popular garden plant (in zones 8 and 9) and house plant, tolerating low temperatures but not freezing.
Pellaea rotundifolia is a compact, evergreen fern that can have more than 30 pairs of round, dark-green, leathery pinnae on fronds up to 18 in (460 mm) in length. The Latin specific epithet rotundifolia means “round-leaved”.
It needs acidic and well-drained soil; it does not appreciate the moist, humid conditions that most ferns require so does well with minimal watering.
This plant has gained the Royal Horticultural Society’s Award of Garden Merit.
II. How to Grow and Care
Sunlight
Button ferns require medium to bright indirect light. They can also tolerate lower-light conditions as long as natural light is present, such as from a north-facing window. Keep button ferns out of direct sunlight, which can burn the leaves.
Temperature and Humidity
Button ferns do best in warm conditions with moderate humidity. Give them temperatures between 65°F and 80°F and 40 to 50 percent humidity.
If your plant seems dry and crispy and you’ve been watering regularly, you can run a humidifier nearby to add more moisture to the air around your plant.
Watering
Button ferns thrive with moisture, and their soil should never be allowed to dry out completely. Water when the top of the soil is just beginning to look dry.
Make sure your plant drains fully after watering and doesn’t sit in water, which can lead to root rot.
Soil
Plant your button fern in a light, well-drained potting mix. Standard houseplant potting mix typically works well. You can also make your own mix by combining one part peat moss or coconut coir, one part perlite, and one part vermiculite.
Fertilizing
Button ferns don’t need much fertilizer. However, you can give them a balanced liquid houseplant fertilizer diluted to half strength once every two months or so during the growing season.
Start fertilizing when you see new growth in late winter or early spring, then stop fertilizing when days shorten in fall.
Propagation
Propagating the Button Fern by division can be an enjoyable way to expand your collection or share with fellow plant enthusiasts.
- Choose the Right Time
The best time to propagate Button Ferns is during the spring or early summer when the plant is actively growing.
- Remove the Plant
Carefully take the Button Fern out of its pot. Gently shake or brush off excess soil from the roots so you can clearly see the plant’s structure.
- Divide the Plant
Look for natural divisions in the root system where the fern appears to have formed distinct clumps. Using a sharp knife or a pair of scissors, cut the root ball into sections, ensuring each new section has a portion of the roots and several fronds.
- Pot Up the Divisions
Fill small pots with a suitable potting mix. Plant each division at the same depth it was growing previously. Gently firm the soil around the roots and water well to settle the soil and eliminate air pockets.
- Care After Propagation
Place the newly potted divisions in a location where they will receive bright, indirect light. Maintain high humidity around the plants, either by misting regularly, using a pebble tray, or placing a humidifier nearby. Keep the soil consistently moist but not waterlogged.
- Monitor Growth
In the weeks following propagation, watch for new growth as a sign that the divisions are establishing themselves. Continue providing optimal care conditions to support their development.
Pottig and Repotting
Since button ferns aren’t heavy feeders and grow relatively slowly, you can expect to repot them every three years or so. Use fresh soil and only go up one pot size. If you notice roots growing out of the holes in the bottom of the pot or filling the container, that’s a sign to repot sooner.
Pests and Diseases
The Button Fern is generally easy to care for, but like all plants, it can encounter pests, diseases, and common problems.
- Common Pests
Spider Mites: These tiny pests thrive in dry conditions and can cause the leaves to look speckled and dull. If an infestation occurs, increase humidity around the plant and treat it with insecticidal soap or neem oil.
Mealybugs: Identified by their cottony white appearance, they suck sap from the plant, weakening it. Remove them manually with a cotton swab dipped in alcohol or use insecticidal soap.
Scale insects: Hard or soft-bodied insects that attach themselves to the stems or leaves, causing yellowing and growth stunting. Scrape off with a fingernail or use a cotton swab dipped in rubbing alcohol. Insecticidal soap or neem oil may also be used.
Aphids: These small, sap-sucking insects can cluster on new growth or the undersides of leaves, causing yellowing or distorted growth. To treat infestations, rinse the plant with water or use insecticidal soap.
- Common Diseases
Root rot: Overwatering is a common issue that leads to root rot. Ensure the pot has good drainage and the soil does not remain soggy. Let the top inch of soil dry out between waterings.
Fungal Diseases: High humidity without proper air circulation can lead to fungal diseases. Make sure the plant is in a well-ventilated area, and reduce humidity if you notice fungal growth.
- Common Problems
Brown Leaf Tips: This can be caused by low humidity, over-fertilization, or exposure to chemicals in tap water. Increase humidity around the plant and use rainwater or distilled water for watering if possible. Fertilize sparingly.
Yellowing Leaves: Overwatering, poor drainage, or a lack of nutrients can cause leaves to turn yellow. Adjust watering practices and consider repotting the fern in fresh potting mix if drainage is poor.
Leggy Growth: Insufficient light can cause the Button Fern to stretch towards the light source, leading to leggy growth. Move the plant to a brighter location with indirect light.
III. Uses and Benefits
The Button Fern is an ornamental plant that can be grown indoors or in shaded outdoor settings. Its drought tolerance makes it suitable for rock gardens and complements other drought-resistant plants.
Besides its ornamental value, Pellaea rotundifolia can help purify the air and increase humidity levels in indoor environments, contributing to a healthier living space.
