Discover exactly how to propagate ferns with our step by step guide from head gardener Mat Reese. Photographs by Jason Ingram
Ferns are useful plants for a wide range of situations, including shade. You can propagate ferns by several methods, including by division, taking leaf clippings, and propagating from spores.
If you want to gradually increase your stock, the easiest way to propagate ferns is by dividing plants in the garden in spring. The potted divisions should be secured in a shaded cold frame until fern roots have developed.
Ferns are most readily propagated in larger numbers using spores. Spores are produced on the undersides of the fern fronds in small capsules called sporangia.
When ripe, the sporangia shed thousands of spores that are dispersed by the wind. If they have landed in a suitable position, the spores will then form a heart-shaped structure called a prothallus, which will then go on to produce a fern. This process will only be successful in continuous dampness, in both natural and controlled environments.
The time to complete this cycle varies. Adiantums for example, may be ready for pricking out in as little as six weeks, while others may take a few months. It is not uncommon to find rogue plants as spores waft about on the slightest breath, and it is therefore important to keep everything sterile.
Ferns are unique vascular plants that have existed for over 300 million years. Their graceful, feathery fronds and lush green colors make them popular houseplants and garden plants. But what really makes ferns special is how they grow and spread via underground stems called rhizomes. This gives ferns an ethereal, magical quality unlike other plants.
In this article, we will explore the mystical world of fern growth and reproduction. We will look at:
- What a rhizome is and how ferns use it to grow
- How new roots and leaves sprout from rhizome tips
- How rhizomes branch and spread to create new ferns
- The advantages of rhizome growth
- The full lifecycle of a fern
So let’s uncover the secrets behind the fairy-like growth of ferns from rhizomes!
What is a Rhizome?
A rhizome is a creeping underground stem that grows horizontally. It is the main method of vegetation reproduction and spread for ferns. The rhizome grows just below the soil surface and contains nodes along its length. Roots grow from the bottom of the rhizome into the soil, anchoring the plant. Leaves emerge from the top through the soil.
The rhizome continues extending itself, producing new roots, leaves and branches as it goes. Mature ferns form extensive underground rhizome systems that continually give rise to new plants. The rhizome stores nutrients for future growth and survives the winter in temperate climates.
Sprouting of Roots and Leaves
In most ferns both roots and leaves sprout from the very tip or apex of the rhizome as it extends itself. This is what gives ferns their special magical quality. Imagine an underground stem constantly pushing forward, sending out new root and leaf pairs from its growing end. This results in a sequence of root and leaf pairs along the rhizome’s length as it grows.
The synchronized sprouting of new roots and leaves from the rhizome tip occurs in a few simple steps:
- The fern rhizome apex meristem (a tissue of constantly dividing cells) pushes forward.
- When the apex reaches a certain length, new root primordia form from the bottom side.
- At the same time on the top side, tiny crumpled leaf primordia start developing.
- As the tip keeps extending, the primordia grow larger, eventually breaking through the soil.
- Mature segmented roots and fully unfurled leaves emerge!
This synchronized production of roots and leaves gives ferns their iconic frond and root growth pattern as the rhizome branches underground.
Branching and Spreading Rhizomes
In addition to producing roots and leaves, rhizomes also branch frequently to form new growing tips. The main rhizome apex continues extending itself straight. Meanwhile, smaller lateral bud meristems on the sides start developing into branches.
These lateral branches emerge from the top side of the rhizome, opposite the roots. The branch apex becomes the new active growing tip, repeating the cycle of root and leaf generation. Branching causes the rhizome system to become larger and more complex over time.
As the branching rhizomes spread outward underground, they give rise to new ferns scattered apart. The mother fern is genetically identical to her offspring. In this way, one fern can eventually spread into a large lush colony!
Advantages of Rhizome Growth
The rhizome growth pattern provides ferns with many advantages:
- Easy propagation and cloning – branched rhizome tips give rise to identical new plants
- Ability to reproduce readily and spread quickly
- Greater adaptability and resilience – if one plant dies, the interconnected colony may live on
- Resource sharing through the rhizome system allows faster growth
- Can regenerate from rhizome fragments; difficult to eliminate all plants
- New sprouts can emerge farther away in favorable microclimates
- Flexibility in responding to environmental conditions
- Persistence through underground rhizome even if aboveground fronds die back
These traits make ferns highly successful! They thrive in forest understories and spread readily in moist, shaded environments.
The Fern Lifecycle
Now let’s quickly review the full lifecycle of a typical fern:
- It starts from a haploid spore, which germinates into a tiny gametophyte plant.
- The gametophyte bears male and female reproductive organs, which unite to form a diploid zygote.
- The zygote grows into a young diploid sporophyte fern plant.
- The sporophyte fern grows its rhizome system, generating new roots, leaves, and branches.
- Older fronds bear sporangia on their undersides – cases containing haploid spores.
- The spores are released, starting the cycle again!
The Magic of Fern Rhizome Growth
The ability of ferns to endlessly generate new roots and leaves from their extending rhizome tips seems almost supernatural. As the rhizome stretches horizontally underground, it appears like a magical, living entity.
Understanding the biology behind the spreading rhizome system and synchronized production of roots and leaves demystifies fern growth. But it does not remove their wonder. Ferns have thrived for eons using the magical rhizome strategy. Their ethereal beauty and ancient resilience continues captivating botanists and plant lovers today.
How to propagate ferns
For the gardener, the most general means of propagating ferns is by spores. These spores (fine, dust-like particles similar in some ways to pollen but able to generate a new plant) are contained in small capsules – called sporangia – on the underside of the fronds, as you can see in the Asplenium scolopendrium above. Provided you can supply heat, ferns can be propagated year-round, otherwise, March and July are the best months.
Periodically examine the fern carefully and when these small capsules turn brown (but before they have burst) cut the frond and wrap it up in smooth, white paper.
After a day or two, unwrap the frond, being mindful not to spill any of the fine brown dust, which is composed of millions of minute spores.
For fern compost, I use a 50/50 mix of John Innes seed compost and a peat alternative. Place in a sterilised container or pot and firm level. Cover the compost with a paper towel and scald with boiling water to sterilise the soil. Once the compost has cooled, remove the towel and sow the spores immediately. The spores can be sown in the same way as seeds, thinly over the surface of the compost.
Quickly cover with a lid or plastic bag to prevent contamination. It is essential to keep the compost moist for germination to occur, but do not water from above. Instead, stand pots in a saucer of water. Place in a shady position.
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FAQ
What structure do fern roots grow from?
Fern stems (rhizomes) are often inconspicuous because they generally grow below the surface of the substrate in which the fern is growing. This substrate can be soil, moss or duff. People often confuse rhizomes with roots. Fern roots are generally thin and wiry in texture and grow along the stem.
What do ferns grow from?
Ferns are very easy to grow from spores and although it takes a number of years, it’s rewarding and you can grow huge numbers of ferns for free!
Do ferns have leaves and roots?
Ferns also contain true roots, stems and leaves. The fern leaves are considered to be megaphylls, meaning they have several vascular strands within them.
Do ferns grow from spores or leaves?
Unsourced material may be challenged and removed. The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (land plants with vascular tissues such as xylem and phloem) that reproduce via spores and have neither seeds nor flowers.
Do ferns have roots?
True ferns, for example Dryopteris and Polypodium. The sporophyte of Psilotum and relatives displays a dichotomic branching stem. Plants of the genus Psilotum do not have true roots, but underground rhizomes that can take up water and nutrients from the soil. Psilotum. Most known horsetails are fossil. Nowadays we only know the genus Equisetum.
Where do fern roots grow?
In living trunks, root climbers and epiphytes mostly attach to the decomposing parts of the root mantle. The vine interpretation is consistent with the observation that the roots of both ferns tend to run in parallel inside the trunk. This would suggest downward growing roots near the trunk base.
How do ferns grow?
Ferns grow in full to part sun and well-drained to dry soils. They form a mat of foliage that is 1 to 2 feet tall. When growing in ideal conditions, ferns can spread aggressively.