Ferns – More Than Just Plants for Shade

When we think of ferns, many of us picture lush, green foliage growing beneath trees, along woodland paths or beside a shaded stream. And while ferns certainly excel in these situations, there's much more to this fascinating group of plants than first meets the eye.

From bold, architectural evergreen specimens to delicate, finely divided foliage, silvery leaves and varieties that develop beautiful autumn colours, ferns offer an enormous range of possibilities for the garden.

They're also rather unusual plants. Unlike most of the familiar flowering perennials we grow, ferns don't produce flowers or seeds. Their life cycle is quite different, and understanding a little about how they grow and reproduce makes them all the more interesting.

Whether you're looking to bring life to a shady corner, soften the edges of a pathway, create a naturalistic planting scheme or add texture to a container display, there's probably a fern worth considering.

Here we see a mixture of ferns planted in a raised bed and some urns in a Japanese style garden display
- CC0 licensed photo by Mohammed Kateregga

What Exactly Is a Fern?

Ferns are an ancient group of vascular plants, meaning they have specialised tissues that transport water and nutrients throughout the plant, just as flowering plants do.

However, ferns evolved long before flowering plants appeared, and they reproduce using spores rather than flowers and seeds.

The familiar leafy part of a fern is called a frond. Depending on the species, fronds may be broad and undivided, finely feathered, upright, arching or spreading.

Many ferns produce their new fronds in spring as tightly coiled structures, sometimes called fiddleheads or croziers. These gradually unfurl as they grow, creating one of the most attractive displays of the gardening year.

How Do Ferns Reproduce?

Turn over a mature fern frond and you may notice rows or clusters of small brown markings on its underside.

These are often mistaken for pests or signs of disease, but they're usually perfectly natural.

The markings are called sori, and each contains structures known as sporangia, which produce and release spores.

Above you can see the fern sori, those brown spots underneath the leaves which are sometimes mistaken for fungus or disease but are part of the reproductive cycle of the plant.
- Photo by Derek Keats, Flickr (CC BY-SA 2.0)
 

When conditions are suitable, a spore can germinate and develop into a tiny, separate plant-like structure called a gametophyte. This produces the reproductive cells needed for fertilisation. In most familiar ferns, a film of water is required for the swimming sperm cells to reach the egg.

Following fertilisation, a new fern plant develops, eventually producing the familiar fronds we recognise.

It's a fascinating life cycle involving two distinct generations, very different from the flowering and seed-setting process of most garden plants.

Not all ferns produce visible sori in exactly the same way, and some species have specialised fertile fronds.

Are Ferns Evergreen?

Some are, but certainly not all.

Evergreen ferns retain much of their foliage throughout winter, providing valuable structure and greenery when herbaceous plants have died back. Examples include many Polystichum, Dryopteris and Asplenium species.

Deciduous ferns lose their fronds in autumn and emerge again in spring. These can be particularly attractive during the growing season, with fresh foliage and, in some cases, excellent autumn colour.

Some ferns are semi-evergreen, retaining foliage through mild winters but losing more of it during prolonged cold weather.

Even evergreen ferns may develop tired or damaged fronds during winter. These can generally be removed in late winter or early spring as fresh growth begins.

Why Grow Ferns in the Garden?

Ferns offer something that flowering plants cannot always provide: long-lasting interest through foliage, form and texture.

• Adding structure: Upright or arching fronds provide shape and definition, especially in shaded borders.
• Creating contrast: Finely divided foliage looks beautiful alongside plants with larger or more rounded leaves.
• Softening hard landscaping: Ferns can soften the edges of paths, steps, walls and shaded seating areas.
• Filling difficult spaces: Many varieties thrive in areas where flowering plants struggle because of limited sunlight.
• Providing year-round interest: Evergreen species keep borders looking established during winter.
• Creating naturalistic planting: Ferns work beautifully in woodland, wildlife-friendly and informal garden designs.

They're also surprisingly versatile in more contemporary gardens. A single architectural fern planted in a simple container can look every bit as effective as a carefully composed woodland border.

Choosing the Right Growing Conditions

Although ferns are commonly associated with damp shade, it's important not to assume that every fern wants exactly the same conditions.

Many thrive in cool, sheltered places with moisture-retentive soil. Others prefer excellent drainage, and some tolerate a surprising amount of sunshine provided their roots don't become excessively dry.

Light and Shade

Partial shade is an excellent starting point for many garden ferns.

The filtered light beneath deciduous trees, the sheltered side of a building or a border receiving morning sun and afternoon shade can provide ideal conditions.

Deep shade is tolerated by some varieties, although growth may be slower and less vigorous where light levels are particularly low.

A number of ferns tolerate more sunlight, especially where the soil remains consistently moist. However, strong afternoon sun combined with dry soil can scorch or damage delicate fronds.

Soil and Moisture

Most commonly grown woodland ferns appreciate soil containing plenty of organic matter, with sufficient moisture during the growing season.

Leaf mould and well-rotted garden compost are particularly useful for improving soil structure and helping it retain moisture.

However, moist soil and waterlogged soil are not the same thing.

Even moisture-loving ferns generally need oxygen around their roots, and prolonged winter waterlogging can cause problems.

Here in the west of Ireland, where rainfall is often plentiful, drainage may be just as important as moisture retention.

For ferns that naturally grow among rocks, on banks or in woodland slopes, good drainage is especially important.

Shelter

Many ferns appreciate protection from strong, drying winds.

Large or finely divided fronds can become damaged in exposed positions, so sheltered gardens, courtyards, woodland edges and protected borders often provide the best growing conditions.

Using Ferns in Garden Design

One of the most appealing things about ferns is how easily they can contribute to very different styles of garden.

Choosing Ferns for Different Garden Situations

Rather than choosing a fern simply because its foliage looks attractive, it's worth considering where it will grow and what you'd like it to contribute to the garden.

The following groups provide a useful starting point, although individual growing requirements can vary between species and cultivars.

Planting Ferns Successfully

Most container-grown hardy ferns can be planted during much of the year, provided the ground isn't frozen or waterlogged and sufficient moisture is available while they establish.

Spring and early autumn are often particularly good planting times.

1. Choose the right position: Match the fern to the available light, soil moisture, drainage and shelter.
2. Prepare the soil: For woodland ferns, incorporate leaf mould or well-rotted compost where appropriate to improve soil structure.
3. Plant at the correct depth: Position the rootball at approximately the same depth it was growing in its pot. Avoid burying the crown of the plant.
4. Water thoroughly: Water after planting and continue to monitor moisture during dry periods, especially in the first growing season.
5. Mulch carefully: A layer of leaf mould or organic mulch can help conserve moisture and suppress weeds, but keep it away from the crown.

Growing Ferns in Containers

Ferns can make excellent container plants, especially where shade limits the range of flowering plants that will perform well.

Choose a pot with adequate drainage holes and use a compost suited to the fern you're growing. Many woodland ferns appreciate an organic-rich compost that holds moisture while allowing excess water to escape.

Containers generally dry out more quickly than garden soil, even in shaded positions, so check moisture regularly during warmer weather.

Conversely, winter rain can leave poorly drained pots excessively wet. Raising containers slightly on pot feet can help improve drainage.

Smaller evergreen ferns are particularly useful in mixed winter displays, providing foliage texture alongside plants such as Heuchera, small evergreens and seasonal bedding.

For a more contemporary effect, try planting a single fern in a simple, generously sized pot and allowing its foliage to provide the main display.

Caring for Ferns Throughout the Year

Watering

Newly planted ferns need regular attention until their roots become established.

Once established, watering requirements depend on the species, soil and growing position. Moisture-loving woodland ferns may need additional water during prolonged dry weather, while more drought-tolerant species can cope with less.

Feeding

Most garden ferns aren't particularly demanding feeders.

An annual application of leaf mould or well-rotted organic matter is often sufficient for ferns growing in reasonably fertile garden soil.

Container-grown plants may benefit from occasional feeding during the growing season, although excessive fertiliser is generally unnecessary.

Pruning and Tidying

Deciduous ferns can be tidied once their old fronds have died back, although leaving the foliage in place over winter can offer some protection to the crown.

Evergreen ferns usually need only the removal of old, damaged or untidy fronds, preferably as fresh growth begins in spring.

Take care not to damage the emerging croziers when cutting away old foliage.

Dividing Ferns

Many clump-forming ferns can be propagated by division, although the method depends on the species and its growth habit.

Spring is often a suitable time to divide established clumps, ensuring each division has healthy roots and growing points.

However, not every fern responds well to division, and some are better propagated by spores or other specialised methods.

Common Problems with Ferns

Ferns are generally reliable garden plants when grown in suitable conditions, but a few problems can occur.

• Brown or scorched fronds: Often caused by excessive sunshine, dry soil or exposure to drying winds.
• Yellowing or poor growth: May indicate unsuitable moisture conditions, poor drainage or an inappropriate growing position.
• Rotting crowns: Can occur where plants are buried too deeply or remain in persistently waterlogged soil.
• Slug and snail damage: Tender emerging fronds can occasionally be damaged, particularly during damp spring weather.
• Winter damage: Evergreen fronds may become brown or tatty after severe frost or exposure. Remove damaged foliage when new growth begins.

And remember, brown markings on the undersides of mature fronds may simply be the fern's natural spore-producing structures rather than a problem requiring treatment.

Combining Ferns with Other Plants

Ferns are especially effective when used to contrast with different leaf shapes, colours and flowering habits.

In a shaded border, the fine foliage of a Lady Fern can look beautiful alongside the larger leaves of Hostas or Bergenia, while the glossy strap-shaped fronds of Hart's Tongue Fern provide a striking contrast with delicate woodland perennials.

Evergreen ferns can also complement shrubs such as Skimmia, Sarcococca and compact Rhododendrons, helping to create planting schemes that retain interest throughout winter.

For a more naturalistic effect, combine ferns with spring bulbs, Hellebores, Epimedium and other shade-tolerant plants, allowing their contrasting growth habits to create interest at different times of year.

It's worth allowing enough room for the ferns to reach their mature spread. Some species remain compact clumps, while others can become substantial plants or spread into colonies.

Final Thoughts

Ferns deserve to be appreciated as much more than simple green plants for shady corners.

With their ancient origins, fascinating life cycle and extraordinary variety of foliage, they offer gardeners an opportunity to create interest through shape, texture and colour rather than relying entirely on flowers.

From compact evergreen varieties for containers and rock gardens to magnificent architectural specimens for woodland borders, there's a fern for many different situations.

The key, as with any plant, is understanding its particular growing requirements and choosing a variety that suits the conditions you can offer.

Whether you're developing a woodland garden, refreshing a shaded border or simply looking for something a little different, ferns are well worth exploring.