Our favourite tree fern, Dicksonia antarctica comes from south-east Australia. They’re evergreen and raise themselves up on thick, fluffy, textual trunks, sometimes to 15ft or more after many years. Their canopy of delicately feathered symmetrical fronds can grow to 12ft across. No wonder then, that theyre called tree ferns. The view from above is unsurpassable. The face that plants show to the sun is often their finest face. In the case of tree ferns, this is undoubtedly true. This is why they are perfect for planting in areas where you can look down on them. For the adventurous, why not build a raised walkway to view them from above? In addition to this, planting them in a grove as part of a woodland walk way can create an enclosed area of dappled shade, ideal for a vast array of underplanting.
Interestingly, the shorter, younger Dicksonia antarctica tend to come from areas where trees such as Eucalyptus are grown for commercial benefit. Once an area is cleared of both tree fern and Eucalyptus the ground is burnt and the pioneer species are the first to grow through. The taller specimens are harvested from areas of hardwood production.
Australian tree ferns are majestic plants that originated in Australia’s lush rainforests. With their tall trunks and arching fronds, they imbue any space with a sense of the tropics. But what lies beneath the surface? In this article, we’ll take an in-depth look at the roots and stems that support these iconic plants.
Overview of Australian Tree Ferns
There are around 30 species of Australian tree ferns, with the most popular being Cyathea cooperi (also called lacy tree fern or scaly tree fern). These plants can grow up to 20 feet tall, with delicate, lacy fronds cascading down.
Tree ferns thrive in warm, humid environments with high rainfall They are often found growing along streams and gullies in rainforests. Their native range stretches along Australia’s east coast, from Cape York Peninsula down to Sydney
The Trunk: Supporting the Fronds
The trunk is the most prominent feature of a tree fern. It emerges from the soil, rising up as a slender column before arching outwards into a crown of fronds.
The trunk consists of a mass of intertwined roots coated in dead frond bases and scales. As new fronds emerge old ones turn brown and cling to the trunk. This gives the trunk its shaggy woolly appearance.
In younger plants, the trunk is relatively smooth. As the fern matures, the persistent petiole bases accumulate, creating characteristic markings on the trunk. The pattern of leaf scars makes each fern unique.
The trunk provides structural support and acts as a conduit to transport water and nutrients up to the foliage. Its narrow girth minimizes water loss through transpiration. A mature tree fern trunk can reach up to 12 inches in diameter.
The Root System: Absorbing Water and Nutrients
While the trunk is the most visible part of a tree fern, the root system is equally important. This hidden network absorbs water and nutrients from the soil.
Tree ferns have two main types of roots:
-
Feeder roots: These fine, hair-like roots grow horizontally just below the soil surface. They efficiently take up moisture and dissolved minerals.
-
Anchor roots: As the name suggests, these thick, woody roots anchor the plant in the ground. They grow down vertically from the base of the trunk.
The shallow feeder roots extend as far as the fronds reach overhead. This expansive network supplies the fern’s considerable water needs. Tree ferns native to tropical rainforests are accustomed to abundant moisture.
Meanwhile, the anchoring roots stabilize the top-heavy plant. They also store carbohydrates and water to help the fern survive dry periods.
The Rhizome: An Ancient Structure
Hidden below ground is another important structure – the rhizome. This horizontal stem connects the fern’s roots and sends up new fronds.
The rhizome is a primitive structure that has allowed tree ferns to persist for 180 million years. Long after the above-ground portion dies back, new growth sprouts from the durable rhizome.
On mature plants, the rhizome becomes large and massive, densely packed with wiry roots. It grows just below the soil surface, extending in all directions. Smaller juvenile plants have a more compact rhizome.
The rhizome’s resilience allows tree ferns to persist through bushfires and other disruptions. If the fronds burn away, new growth will emerge from underground.
Caring for the Roots and Trunk
To keep your tree fern healthy, it helps to understand how to care for the roots and trunk:
-
Plant in well-draining soil. Stagnant moisture can rot the roots and base of the trunk.
-
Provide even moisture. Water thoroughly then allow the top few inches of soil to dry out before watering again.
-
Stake for support if needed. Tree ferns become top-heavy as they mature. Staking prevents the trunk from bending.
-
Remove dead fronds to improve air circulation. Pile mulch around the base, leaving the trunk bare.
-
Watch for sunburn on exposed trunks. Whitewashed or shaded trunks are less prone to burning.
With the right care, the trunk and root system will support lush frond growth for many years to come.
Propagating Tree Ferns
Tree ferns don’t propagate through seeds. Instead, new plants form vegetatively from rhizome cuttings and plantlets that form on mature fronds.
To propagate from the rhizome, carefully divide a mature plant in early spring. Cut away a section of rhizome with some attached roots and growth buds. Replant the rhizome section and maintain warm, humid conditions as it establishes.
For propagation from plantlets, watch for small plantlets forming where frond pinnae meets the rachis. Cut off the plantlet and root it in sterile potting mix. Keep the plantlet enclosed to retain humidity during root establishment.
The Beauty of Australian Tree Ferns
With their prehistoric appeal and lush, tropical foliage, it’s easy to see why Australian tree ferns have stood the test of time. Their intricate root systems and ever-renewing rhizomes allow them to persist through harsh conditions.
If given the right care, these living fossils can thrive for decades, even centuries. Their gracefully arching fronds bring a sense of tranquility and provide refreshing greenery. Whether in a garden or home, Australian tree ferns are unrivaled for their graceful beauty.
How to feed tree ferns
During the spring growing season, feed weekly into the crown of the tree fern as the knuckles start to move and the fronds begin to unfurl. Use a specialist feed – HSK Tree Fern Feed – it is by far the best. If they have suffered a particularly rough winter they will really benefit from this boost.
How to plant a tree fern
Given the cost of tree ferns, the challenge is to have as much of the plant out of the ground as possible. So, when it comes to planting, it’s a question of stability. For the large ones, you can drill a hole into the centre of the trunk (yes, literally drill a hole) and insert a metal rebar to act as an anchor in the ground. You can also wire to guy them to the ground. For smaller trunks, digging a small hole to bury them in works well and the depth of that is dependent on how densely you compact the soil around them. If you have a new house and a new garden (especially in an area where clay predominates) grow them either in a pot or wait for a few years. Ferns are fuss pots and will only grow in good friable, well-drained soil with lots of organic content.