Rumohra adiantiformis [roo-MOH-ruh, ad-ee-an-tih-FOR-mis] known by the common name leatherleaf fern is a fern species from the family Dryopteridaceae.
It is native to a diverse range of countries in the Caribbean, South America, southern Africa, Australasia, Papua New Guinea, New Zealand, and islands in the West Indian Ocean.
The plant is typically grown in gardens as well as indoors.
Common names include:
- Leather Fern
- Leatherleaf Fern
- Leathery Shield Fern
- Iron Fern
- 7-weeks Fern
Commercial production of the leatherleaf fern Rumohra adiantiformis began in Florida during the 1930s. The 1950s saw a major increase in leather leaf fern plantings.
Leatherleaf Fern Care
Size & Growth
Rumohra adiantiformis is an evergreen herbaceous fern species growing up to 2’ – 4’ feet depending on the growing conditions.
The dark green-colored, lacy-looking, finely-cut, glossy, and triangular-shaped leaves or fronds give the plant a tropical appearance.
A feature of the leatherleaf fern distinguishing it from most other fern species is it does not have separate reproductive fronds.
Instead, the reproductive clusters, called sori “fruit dots”, are located on the underside of the dark green leaflets.
Since the fern species spreads slowly, it is suitable for growing in small spaces, pots, and hanging baskets as well.
When grown outdoors, make sure to leave 24” – 36” inches of space between each fern.
The fern is hardy to USDA hardiness zones 9-11.
Flowering and Fragrance
Since Rumohra is a fern species, it does not produce any flowers.
Evergreen year-round.
Holds its deep green color and frond integrity under less-than-ideal circumstances.
Light & Temperature
Adiantiformis prefers a partial shade position with filtered sunlight.
While the plant can survive in full shade, it cannot tolerate full sun and direct sunlight, so be careful not to expose your plant to full and direct sun.
Outdoors, leatherleaf grows best in shady areas but inside will take bright, indirect light.
The plant cannot tolerate temperatures below 24° degrees Fahrenheit (-4° C), so avoid planting them outdoors if you live in an area where the temperature falls below this during winters.
USDA hardiness zone 9 – 11.
Watering and Feeding
Though they are not particularly high-maintenance, leatherleaf ferns do have specific light, soil and water requirements.
While rumohra adiantiformis plants need regular watering to thrive, they can survive with less frequent watering after they are fully established.
However, do not let them completely dry out as they only have moderate drought tolerance.
The plants are also intolerant to water with a high mineral concentration or is salty.
Fertilizing the plant with a half-strength liquid all purpose fertilizer once a month, during the growing season, helps to maintain the color and shine of its foliage.
The frequency and amount of the fertilizer vary according to the type of soil the ferns are planted in.
Do not apply fertilizer to the transplanted rhizomes until they start developing feeder roots.
Soil & Transplanting
The houseplant fern species can grow in loam, clay, or sand, but the soil has to be rich in organic matter, moist, and well-draining.
Expert planters suggest to top-mulch the plant periodically for best results.
It also prefers acidic soil.
Grooming and Maintenance
The fern is a low maintenance plant and doesn’t require much effort from your side.
Cut the old fronds down to the ground with a sharp knife in spring just as the new growth appears.
You may also like the Ghost Fern – Athyrium Hybrida
How To Propagate Leather Fern
Propagation of leather-leaf is performed through spores or rhizome divisions; however, the latter method is mostly preferred by non-commercial planters.
Take about 3” – 5” inches long terminal rhizome cuttings at the beginning of the plant’s growing cycle, in spring, and plant them in separately in potting filled with sterile and well-draining soil.
For best results, include a few leathery fronds in the rhizome cuttings; it improves the ability of rhizome divisions to take roots.
While the leather-leaf fern propagates naturally through spores in mid-summer, the spores are collected and sown by gardeners.
Propagation from spores is done by sowing them on the surface of a sterilized and moist growing medium.
A mixture made from equal parts of loam, coarse sand, peat, and leaf mold is considered the best for growing rumohra adiantiformis through spores.
Iron Fern Pest or Diseases
Leather fern plants can get affected by:
- Mites
- Scale insects
- Fern borers
- Leaf miners
- Mealybugs
- Leafhoppers
The leatherleaf fern is also susceptible to fungal diseases, but most of them are prevented by using sterile tools and growing mediums.
You may also consider applying a fungicide in established plants.
Excessive watering and poor drainage may cause root rot, which then can affect the color of the foliage and may also cause wilting.
Uses For Rumohra Leather Leaf
Rumohra adiantiformis is cultivated as an ornamental plant, mainly as a ground cover, and the cut foliage is also widely used in floral arrangements due to the longevity of its fronds.
The fern species has significant economic importance in Brazil – a large number of local people earn money by wild-harvesting and selling the cut foliage fronds.