Ferns: to grow and plant

Botany

A true testament to the past, ferns are among the first plants to have emerged from water. The oldest appeared nearly 400 million years ago… They were around long before the dinosaurs! Although they have adapted and survived through the ages, they retain a dependency on water, essential for their reproduction. This is why they are primarily found in nature in cool or moist environments. Some of them are even completely aquatic!

A highly diverse plant group, ferns comprise between 9,000 and 13,000 species, found on almost every continent. The majority are native to tropical regions, which explains why they are often cultivated as houseplants. Here, we will discuss hardy ferns that can withstand frost, originating from temperate zones. Many species can be observed in the wild in France. You can easily find them in forests, along streams, or in marshy soils. Some grow directly on the ground, while others thrive in rock crevices, on walls, or even as epiphytes on trees!

Asplenium trichomanes and Asplenium adiantum-nigrum: botanical plate

Ferns form a large group that includes plants from various families, such as Dryopteridaceae, Polypodiaceae, or Woodsia. They, along with horsetails, constitute an even broader group known as Pteridophyta. Who would have thought, however, that ferns, with their large fronds, are closely related to horsetails with their straight, robust stems and no leaves?

Ferns have their own unique vocabulary: we do not refer to leaves but to fronds, which initially are coiled in croziers, and they do not produce seeds but spores, grouped in sacs called sori!

Ferns can develop in an upright tuft and sometimes form small stumps, or even true stipes (trunks) for arborescent species! As for the spreading ferns, they crawl and spread thanks to running rhizomes. The height of ferns varies greatly. Asplenium are among the shortest, while Dryopteris are much more imposing. Osmunda regalis is one of the largest hardy species: it can reach up to two metres in height!

Initially, the fronds of ferns are coiled in croziers, at the centre of the tuft. Then they unfurl, revealing elegant fronds, sometimes very large. What a sight to see ferns unfurl their fronds in spring! In most cases, they are a lovely light green colour. They will then take on darker shades over time. Ferns offer a beautiful palette of green, in all its nuances: from bright yellow-green to dark, deep green, sometimes marked with purple.

It is the Asian ferns that offer the most varied hues. For instance, Athyrium niponicum ‘Pictum’ has splendid silver foliage tinged with purple. As for Dryopteris erythrosora, it bears stunning fronds that change colour over time. Initially orange-pink when they unfurl in spring, they later turn bronze, then dark green.

Ferns offer a beautiful diversity of foliage! Most of the time, their fronds are long, slender, and highly divided! This gives them their characteristic lightness, adding a lot of graphic appeal to flower beds. This is why we love them so much… Few plants possess such graceful and elegant foliage! Lacking flowers, ferns seem to have focused entirely on their foliage, and it is a beautiful success! Some species have much less divided fronds, such as Onoclea sensibilis, and can even have an entire lamina, like Scolopendre (Phyllitis scolopendrium)!

The fronds of ferns are first coiled in croziers before unfurling! From left to right, Dryopteris filix-mas, Dryopteris wallichiana, and Matteuccia struthiopteris (photo Muriel Bendel)

Many species are evergreen! This is the case for Dryopteris erythrosora, Polystichum setiferum or Phyllitis scolopendrium. They remain decorative throughout the year! Others are deciduous, such as Athyrium, Adiantum or Osmunda. Their foliage dries in autumn, and new fronds unfurl in spring.

The fronds of ferns can take on stunning hues! From top to bottom, Dryopteris erythrosora, Dryopteris cycadina, and Athyrium niponicum var. pictum (photo Kristine Paulus)

Ferns possess rhizomes, underground stems that store nutrient reserves. These rhizomes can be running and allow the plant to spread. It is then easy to multiply them by dividing these rhizomes. The roots develop at the level of the rhizomes. They are superficial and do not penetrate deeply into the soil.

The particularity of ferns is that they do not produce flowers or seeds. In their time, plants simply had not yet invented flowers for reproduction! Instead, ferns have spores, very fine particles resembling dust, which they produce in enormous quantities. They are contained in sacs called sores, often grouped on the underside of the fronds. When mature, they open and release the spores, which are carried away by the wind. Some ferns develop fertile fronds in summer, which look quite different from the other fronds, and whose function is to bear the spores.

When they fall to the ground, they germinate to give rise to prothalli, tiny organisms resembling moss that bear the sexual organs. After fertilization, new ferns will grow from these prothalli.

The sori of ferns are grouped on the underside of the fronds. When they reach maturity, they open and release the spores. Here, a frond of Polypodium vulgare (photo Matthieu Gauvain)

Ferns are also good utilitarian plants. Some are edible! They are useful in the garden: you can make fern manure or use them as a compost activator.

The main species and varieties of ferns

The most popular varieties

Our favourite varieties

Other varieties to discover

Dryopteris erythrosora - Copper Fern

Very popular, it’s our star variety! This is a vigorous Asian fern with evergreen foliage. It has large triangular fronds that are particularly decorative. These change colour: first pink when young, they then take on bronze and dark green hues. They are borne on red petioles.

• Height at maturity 70 cm

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Polystichum polyblepharum - Japanese Lace Fern

Also known as 'Bear's Paw', this fern native to Asia is very popular! With its large dark green fronds, it is particularly elegant. Its very spreading fronds give it a ground-covering appearance. It is evergreen.

• Height at maturity 60 cm

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Athyrium niponicum var. pictum - Painted Fern

This Asian variety stands out for its surprising silvery-grey foliage, tinged with purple. It is a small fern that grows slowly and never becomes very tall. It is deciduous and only reveals its new fronds at the end of spring. It spreads through its running rhizomes. If the growing conditions are suitable, it can form fairly dense and extensive mats.

• Height at maturity 30 cm

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Asplenium trichomanes

This is a small evergreen fern, quite common in the wild in France, on stone walls in villages or on church walls... Its linear fronds consist of short rounded leaflets arranged around a black rachis. It is undemanding and tolerates drought. Plant it on a wall or in rockery, preferably in a shaded position.

• Height at maturity 15 cm

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Phyllitis scolopendrium

Also known as Scolopendrium or Asplenium scolopendrium, this evergreen species, quite common in France, is one of the few ferns with entire, undivided fronds. Grow it in shade, in calcareous and well-drained soil! It easily finds its place in a shaded rockery. There are varieties with plicate foliage, such as Phyllitis scolopendrium 'Cristatum' or 'Undulatum'

• Height at maturity 45 cm

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Matteuccia struthiopteris - Ostrich Fern

With its large upright fronds of a beautiful light green colour, this fern is particularly elegant. Also known as Ostrich Fern, it has a lot of charm and creates a majestic effect. In summer, fertile fronds emerge from the centre of the crown of leaves. Naturally growing on the edges of streams, it is perfect for enlivening the banks of a pond! We recommend planting it in groups of 5 to 10 plants!

• Height at maturity 80 cm

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Adiantum pedatum

This deciduous fern stands out for its extremely light and fine foliage, with a fragile appearance. It has a black petiole, which provides a remarkable contrast with the light green of its leaves. It is a fern that brings a great sense of freshness! It prefers slightly acidic soils but tolerates calcareous conditions.

• Height at maturity 60 cm

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Osmunda regalis - Royal Fern

The Royal Osmunda is a majestic fern that bears large deciduous fronds! It takes on splendid colours in autumn. It forms a stipe and bears fertile fronds in summer that will release spores. Naturally growing on riverbanks, it needs moist soil and will thrive at the edge of a pond. It does not like calcareous soils.

• Flowering time June to August
• Height at maturity 2 m

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Onoclea sensibilis

This is a small fern that can be used as ground cover. It has a running rhizome and quickly forms a thick mat. It is distinguished by its surprising, triangular and broad fronds, which take on beautiful colours, often yellow-green, sometimes tinged with red.

• Height at maturity 60 cm

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Blechnum spicant - Hard Fern

The Blechnum in spike is a persistent fern that bears linear fronds. In summer, the fertile fronds stand upright in the centre of the tuft. It is found in the wild in the forests of France, in moist soil. It dislikes calcareous soils!

• Height at maturity 40 cm

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Dryopteris filix-mas - Male Fern

This is the male fern, a species quite common in the forests of France. It forms tufts from which large dark green, deciduous fronds emerge. Undemanding, it is easy to grow and tolerates calcareous soils. It is a very classic fern.

• Height at maturity 1 m

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Dicksonia antarctica - Tree Fern

An exceptional plant native to Australia! It forms a true trunk, thick and imposing, at the top of which it unfurls its gigantic fronds. A very elegant habit that brings a lot of exoticism. It grows slowly, reaching about ten metres in height. It can withstand temperatures down to -8 °C.

• Height at maturity 6 m

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Cyrtomium falcatum

This evergreen fern, native to Asia, bears tough and glossy dark green fronds. It has rather coarse foliage, less divided than most ferns, somewhat reminiscent of that of mahonias. It tolerates temporary drought and slightly calcareous soils! It also adapts well to pot or rockery culture.

• Height at maturity 60 cm

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Polypodium vulgare - Rockcap Fern

This is a small evergreen fern with a running rhizome. It is easily found in the wild in France, on stone walls, between rocks, or on the trunks of trees in forests. It tolerates drought and calcareous soils. You can grow it on a wall, in rockery, or even place it on the stump of a dead tree!

• Height at maturity 25 cm

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Athyrium otophorum var. okanum - Eared Lady Fern

This is a small deciduous fern native to Asia. It is loved for the graphic design and original colour of its fronds! These initially have a slightly golden and silvery hue, then turn blue-green. They are delicately tinged with russet and have purple veins.

• Height at maturity 40 cm

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Dryopteris affinis - Scaly Male Fern

This semi-evergreen fern forms tufts from which large dark green fronds emerge, measuring up to 1.5 m in length. It is a classic fern, quite close to Dryopteris filix-mas. It has given rise to a few original varieties, such as Dryopteris affinis 'Cristata'.

• Height at maturity 1,20 m

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Dryopteris sieboldii - Japanese Fern

This evergreen fern, which grows wild in Asia in mountain forests, bears thick and undivided fronds, making it truly unique! They are composed of large, very broad pinnules, dark green. It resembles no other. It grows slowly and thrives in shaded rockery.

• Flowering time February
• Height at maturity 60 cm

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Dryopteris wallichiana - Wood Fern

Very elegant, this fern will charm you with its graphic design. It bears beautiful fronds of a tender and luminous green, turning yellow in spring, and which are nicely highlighted by the dark central vein. It is semi-evergreen and adapts well to container culture.

• Height at maturity 1,50 m

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Dryopteris goldieana - Giant wood fern

This deciduous fern, which comes from North America, is one of the largest species of Dryopteris. The young fronds have a superb yellow-green hue. They then become light green, and later take on bronze highlights. It appreciates calcareous soils!

• Height at maturity 1,50 m

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Cheilanthes lanosa

This small fern, native to North America, is particularly adapted to sun and drought! It bears grey-green fronds. Plant it in well-drained soil: it does not tolerate excess moisture in winter. You can place it in rockery, alongside blue fescue.

• Height at maturity 30 cm

See the product sheet

To plant the right fern in the right place, discover our advice sheet: “Ferns: how to choose them”

Young plantation

Where to plant?

Two conditions are essential for successfully growing ferns: coolness and shade! These are plants that naturally grow in undergrowth: they will thrive at the foot of trees or bushes, or sheltered by walls, in the shade of a house. However, they do need some light and will prefer light shade to dense shade. They enjoy cool, even moist soils. Osmunda, Matteuccia, and Athyrium will thrive on the banks of ponds. However, once well established, many species can prosper in dry shade. This is particularly true for the Male Fern. Ferns will appreciate being planted out of the wind.

Naturally growing in forests, ferns prefer rich, light, and humus-bearing soils, and they will thrive in a good woodland soil. To enrich your soil, you can add compost at planting time. If your ground is sandy, add organic matter to make it richer and less dry! If it is particularly heavy, you can also lighten it with leaf mould. Ferns do not require deep soil, as their root system is quite shallow.

The majority of species prefer rather acidic soils and will struggle to grow in calcareous ground. Do not hesitate to add a bit of heather soil. However, aspleniums prefer calcareous soils.

Some ferns, such as aspleniums and polypodies, thrive in rockeries or on low walls. You can even consider installing them on stumps of dead trees! Finally, some varieties, such as Asplenium scolopendrium or Athyrium niponicum ‘Pictum’ adapt well to living walls.

Although most ferns thrive in open ground and shade, there are exceptions! Here, an Asplenium trichomanes on a rocky wall, a polypody as an epiphyte on a tree trunk, and Dryopteris wallichiana in the forest

When to plant?

Plant your ferns in autumn or in spring, avoiding periods of frost or intense heat, ideally planting from September to November or from March to April, even May.

How to plant?

Planting in open ground:

Ferns appreciate rich, humus-bearing, and light soils: do not hesitate to add organic matter to improve your soil.

1. Start by placing the root ball in a basin filled with water to moisten it.
2. In the meantime, dig a planting hole about twice the size of the root ball.
3. Place leaf mould at the bottom, and possibly heather soil if your soil is rather calcareous.
4. Then position the fern, replace the soil, and gently firm it down.
5. Water generously.
6. Mulch with pine bark or ramial chipped wood (RCW) to keep the soil cool.

Continue to water regularly in the weeks following planting, and afterwards in case of drought.

Pot planting:

Choose a large enough container and place a layer of gravel or clay balls at the bottom. Fill the pot with substrate, ideally a mix of potting soil and heather soil. Install the fern, fill in by replacing the soil around it, then water. Ferns are sensitive to overly dry atmospheres, so do not hesitate to mist the leaves regularly in summer.

For more information on planting ferns, visit our practical sheet: “Planting Ferns”

Maintenance

Ferns require very little maintenance! It is rare for them to become diseased or attacked by pests. You can plant them in an area of the garden left quite natural, or in a space that is difficult to maintain, and let them grow naturally without intervention.

If you are growing them in pots, water regularly to keep the substrate moist. Those growing in the ground will need to be watered during dry spells. Don’t hesitate to add a bit of compost at the base of your ferns in spring. We recommend placing a layer of mulch at the base of your ferns (ramial chipped wood, dried fronds, or pine bark). This will help keep the soil cool and limit the growth of weeds. Do not leave the soil naked!

Ferns need to be pruned each year down to the ground. Wait until early spring to cut back the dried fronds, being very careful not to cut the new shoots in the centre. By leaving them in place throughout the winter, they will protect the stump from the cold, especially the small croziers at the centre of the clump. Use pruning shears to cut the old fronds. This will make room for the development of new fronds.

→ Follow our practical tips to prune ferns in our tutorial.

Multiplication

There are different techniques for propagating ferns. They do not produce seeds, but it is possible to sow spores. Some ferns can be easily propagated vegetatively: by division, or, for a few rare varieties, by taking bulblets.

Sowing Spores

Ferns are unique plants that do not produce seeds, so sowing spores is quite technical and delicate to carry out, but you can succeed by following a few simple rules. It is essential to maintain sufficient moisture, which is crucial for reproduction, not to cover the spores with soil, and to place the sowing in a bright location, out of direct sunlight. One of the biggest problems is the appearance of mosses or fungi.

Harvest the spores when they are mature, in summer or autumn (depending on the species!). You can identify their maturity by the brown colour of the sori. Take a part of the frond and place it in an envelope or paper bag. It will release the spores as it dries, in a few days. We recommend sowing them immediately. You will have a better chance of success!

1. Start by preparing the substrate: Mix potting soil and sand, possibly adding peat, then sieve it to obtain a fine and homogeneous substrate.
2. Water to moisten it.
3. Then, we recommend sterilising it by microwaving for 5 to 10 minutes. This operation will prevent the development of mosses or fungi (or other seeds if you use soil from your garden).
4. Place the substrate in a seed tray, unperforated, to retain moisture. You can choose a clear plastic or glass container with a lid. In any case, it must be clean and sterilised. A substrate thickness of a few centimetres is sufficient.
5. Let the substrate cool, then level the surface by lightly pressing down.
6. Then scatter the spores on the surface, but do not cover them! As they are tiny, a small volume of spores is enough to give rise to many ferns.
7. Close the seed tray with a clear lid to retain moisture.
8. Place the seed tray in a bright location, but out of direct sunlight.

The spores will germinate and form a green film on the substrate, after about a month, resembling moss. These are prothalli, small organisms that, after fertilisation, will give rise to ferns in the form we know! Monitor the moisture of the substrate, and do not hesitate to mist if necessary.

Generally, you will need to wait at least six months to see the first small fronds. You can then transplant them. Gently remove the young ferns from the substrate, then replant them in pots filled with potting soil. After a year, you can plant the ferns in your garden.

Also consult our guide “Sowing Fern Spores” and our video tips:

Division

Although this technique is not suitable for all ferns, some of them lend themselves well to division. This will allow you to obtain several plants much more easily and quickly than with sowing spores. Divide them preferably in spring or autumn.

Adiantum pedatum, Athyrium niponicum, Cyrtomium falcatum, and some Dryopteris can be easily propagated by dividing the clumps in spring. To do this, dig up the rootstock, digging wide enough not to damage the roots. Remove any excess soil if necessary. Divide the clump, ensuring to keep enough roots each time. Replant and then water.

Some species have creeping rhizomes, from which new fronds emerge. It is easy to propagate them by dividing these rhizomes. These are the ferns with a creeping habit, such as the Polypodies or Onoclea sensibilis. It is best to intervene in autumn. Dig up the plant and remove the excess soil to expose the rhizome. Cut it into sections with a sharp knife, ensuring to keep some roots and fronds each time. Replant the rhizomes and then water.

The ostrich fern, Matteuccia struthiopteris, is easy to propagate by division. It has a creeping rhizome that forms new clumps by spreading around the main rootstock. Simply take these clumps by separating them.

Propagation by Bulblets

Some ferns develop bulblets, tiny seedlings, clones of the mother plant, directly on their fronds. They will naturally detach, fall to the ground, and form new ferns. This is the case with Polystichum setiferum ‘Proliferum’, Polystichum setiferum ‘Plumosum Densum’, or Asplenium bulbiferum. It is easy to propagate these ferns by taking the bulblets and replanting them.

Prepare a pot with a light and porous substrate, then water. Next, place the bulblets in contact with the soil, laying part of the frond on the ground and lightly burying the bulblets. They will quickly form roots and can begin their growth. Ensure that the substrate remains moist by watering regularly.

Association

Ferns are perfect for creating a natural atmosphere, much like that found in forests. They have a graphic, airy, and wild quality. Plant them in the undergrowth alongside hostas, tricyrtis, or epimediums. They pair very well with other plants that have decorative foliage. In a style that remains wild and natural, you can place ferns at the edge of a pond, as they are suited to cool or even moist soils. For this, choose osmunda or matteuccia, which you will plant alongside marsh iris or Primula bulleyana.

Create a natural atmosphere in the undergrowth with Dryopteris erythrosora, Tricyrtis formosana x hirta (photo Amada44), Hosta ‘Emily Dickinson’ and Epimedium warleyense ‘Orangekonigin’

With their elongated fronds, ferns allow for the creation of a very graphic garden when combined with horsetails, grasses, or bamboos. This will result in a modern garden with clean lines and subdued colours. The tallest ferns provide a very structured aspect when placed at the back of a border. They create a rather understated backdrop in a beautiful green hue that will highlight the more vibrant flowers you can plant in front of them. Ferns also adapt well to pot cultivation and, when placed on a terrace, will bring a lot of natural charm.

Discover many more ideas for pairing ferns in our advice sheet: “Ferns: 9 ideas for easy pairings to succeed”

Did you know?

• An incredible diversity

Ferns surprise with their diversity. Some species are reviviscent: they can completely dry out, appear dead, and come back to life with the first drop of water. Others, entirely aquatic, float on water (some can even be found in France). Some are myrmecophilous: they live in symbiosis with ants, providing them shelter and cover! There are also climbing ferns (Lygodium japonicum)! Others, arborescent, form true trunks! Unfortunately, these are not very hardy and will need to be protected for winter, unless you live in the Mediterranean region.

• A conquering species

The bracken fern, Pteridium aquilinum, is a true conqueror: it easily colonises new spaces, becoming invasive, and resists everything: even fire favours it! It is very difficult to dislodge once it has invaded a plot of land. Its spores can travel 3,000 kilometres! It even prevents other plants from growing.

• Popular beliefs

Ferns are linked to many myths and legends. Their mode of reproduction and the absence of flowers have often fascinated and raised questions. They gave rise to the legend of the fern flower. In Eastern European mythology, this very rare flower would grant great powers to the person who discovers it. It was also believed that their seeds had the power to make one invisible. They had to be harvested at midnight, on the eve of St. John’s Day. It took a long time to understand that ferns do not produce seeds!

• Edible ferns

Some species are edible! This is the case for the croziers of Matteuccia struthiopteris, called fiddleheads, which are particularly appreciated in Quebec. They must be cooked in boiling water or steamed. In Asia, the bracken fern is commonly consumed, after being prepared to remove its toxicity. Less dangerous, the rootstock of Polypodium vulgare has a taste of liquorice.

• As mulch!

Some ferns, like Dryopteris filix-mas, are deciduous: their fronds dry out in autumn. Take advantage of this to collect them, as they make excellent mulch! Harvest them when they are dry, cut the largest ones with pruning shears, and place them at the base of your plants. They will prevent weeds from growing, maintain soil moisture, and, as they decompose, they provide organic matter that enriches your soil with potassium! They also have antifungal properties and repel slugs. You can use fronds of bracken fern, which you can find in nature, in acidic woodland. Fern fronds can also provide protection against the cold: place them against your most delicate plants, for example by tucking them under a winter cover. You can also make fern manure, effective for repelling insects (aphids, scale insects…), using Dryopteris filix-mas or the bracken fern (Pteridium aquilinum).