Fern Care: How to look after indoor and outdoor ferns
Ferns are popular because of their suitability as indoor plants. But the group has even more to offer, as most thrive outdoors, growing well in shaded spots where other plants struggle. They could be just the plant to grow in a courtyard or small shaded garden to create a cool, lush look.
Ferns are ancient plants. What sets them apart from most other garden plants is that they don’t have flowers. Instead of producing flowers and seeds, ferns reproduce via spores, which form on the underside of their fronds (the fern equivalent of a leaf). Mature spores are scattered in the air, fall on moist surfaces and eventually form a baby plant. Some ferns also spread via rhizomes and some produce small plantlets on their leaves.
Popular fern varieties
There are many different ferns, offering a range of sizes, shapes and colours. One of the most striking is the bird’s-nest fern (Asplenium nidus), which forms a huge rosette with large fronds. Over time, one can reach 150cm across and form the ideal centrepiece of a rainforest-inspired garden. Grow bird’s nest ferns among trees and combine with shade-loving bromeliads, other ferns or other shade-loving plants such as begonias. Other large ferns include tree ferns and elkhorn ferns (Platycerium bifurcatum).
At the other end of the scale are dainty groundcover ferns such as the robust Pellaea falcata, a small creeping fern that’s native to parts of Australia, New Zealand and even found in India. It grows in shade and spreads happily across the ground to form a clump around 20cm high and wide.
While most ferns are green – ranging from light to very dark greens – some offer colour from rusty brown or red to golden tones. The new fronds of the Australian fern Doodia aspera can show bright red to orange colouration. The new rhizomes of the rabbit’s foot fern (Davallia solida var. fejeensis) are covered with light brown furry growth so they resemble the paw of a rabbit.
Ferns for indoors
For many gardeners, maidenhair fern (Adiantum raddianum ‘Fragrans’) is their first introduction to the world of ferns. These delicate ferns thrive in low light and high humidity, which is why they are often found adding colour, lushness and interest to a bathroom.
Small ferns can also be grown indoors in terrariums or as part of a group of potted plants. Select small ferns and regularly remove large fronds to keep the ferns growing well in the confined space of the terrarium.
For a bold indoor hanging basket grow a Boston fern (Nephrolepis exaltata ‘Bostoniensis’) (pictured). These ferns are more robust than maidenhair ferns and thrive in most well-lit indoor positions including sunrooms and sheltered patios.
Special fern care
Most ferns are robust, low-maintenance plants, but knowing a few tricks keeps them looking good and growing strongly. Ferns generally prefer a shaded spot that’s protected from strong winds, hot sunlight and frost. They need moisture, so grow best with regular watering (especially in summer or in areas with low humidity) or misting. Indoor ferns, such as maidenhair ferns, respond well to regular, light misting and should be kept away from both indoor heaters and air-conditioners.
Most ferns grow in the ground, in soil enriched with aged compost or decomposed leaf mould, but ferns also grow well in containers (including bark- or fibre-lined wire hanging baskets). In pots, select a mix formulated for ferns or indoor plants. To keep their growing environment moist, surround ferns with a layer of organic mulch such as decomposed bark or leaf litter.
These ancient plants don’t like too much fertiliser. In gardens, compost and leaf litter provides plenty of slow-release nutrients but in containers, the occasional liquid feed may be needed, but take care to apply at half strength. Also take care if using any form of pesticide on a fern. Check the label before applying insecticides or fungicides to a fern. Regularly groom ferns to remove tatty, brown or damaged fronds, cutting them off at the base.