Tree Fern 101: From Planting to Winter Protection
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Tree ferns, with their majestic lacy fronds, are perfect for adding a touch of tropical elegance to the garden.
My tree fern is definitely the pride and joy of my back garden.
With their lush, dramatic fronds and sturdy trunks, tree ferns can transform any outdoor space into an oasis, even in the middle of the city.
Whether you’re nurturing an Australian tree fern (Cyathea cooperi) or a hardy Tasmanian tree fern (Dicksonia antarctica), these beauties are surprisingly adaptable.
In this post, I’ll share some tips and tricks on how to grow and care for tree ferns, ensuring they thrive for years to come.
Fun Fact:
Fossil records suggest that tree ferns first appeared on Earth during the late Jurassic period, approximately 180 million years ago.
This means that tree ferns have been thriving on our planet since the time of the dinosaurs.
My Tasmanian Tree Fern (Dicksonia antarctica).
Choosing the Right Tree Fern Species
There are several tree fern species to choose from, each with unique characteristics.
Here are the most popular options:
Australian Tree Fern (Cyathea cooperi):
Known for its fast growth and lacy fronds, this fern is a popular choice.
It can grow up to 15 feet tall and thrives in warm, humid conditions.
The Australian tree fern is also known for its ability to tolerate a variety of soil types, making it versatile for different garden settings.
Tasmanian Tree Fern (Dicksonia antarctica):
This hardy tree fern is more cold-tolerant and has a thicker trunk, making it a great choice for cooler climates.
It grows slowly, reaching heights of up to 20 feet over many years.
The Tasmanian tree fern prefers consistently moist soil and partial shade, making it well-suited for temperate gardens.
Lacy Tree Fern (Sphaeropteris cooperi):
Often confused with the Australian tree fern, the lacy tree fern is distinguished by its more delicate, finely divided fronds.
It can grow rapidly, reaching up to 20 feet in height.
This fern species is ideal for creating a lush, tropical look in the garden and prefers sheltered, humid environments with rich, well-drained soil.
New Zealand tree fern (Cyathea medullaris):
Also known as the black tree fern, is renowned for its striking black trunk and lush, large fronds.
This majestic fern can grow up to 50 feet tall and is a prominent feature in New Zealand's forests.
It thrives in moist, shaded environments, adding a dramatic, tropical touch to any garden.
To learn more about ferns, check out my guide Evergreen Ferns for Year-Round Interest.
Planting Your Tree Fern
Planting a tree fern properly is crucial for its successful growth and development.
Here is how to plant a tree fern:
Selecting the Right Location
Tree ferns thrive in shaded or partially shaded areas that mimic their natural forest habitats.
Choose a location that provides shelter from strong winds and direct midday sun, as these can damage the fronds and inhibit growth.
Ideal spots include the north side of a building, under a canopy of larger trees, or in a shaded garden bed.
A tree fern is an excellent choice for an east facing garden.
Preparing the Soil
Tree ferns prefer well-drained, rich, and organic soil.
To prepare the planting site:
Soil Amendment:
Incorporate plenty of organic matter, such as compost, leaf mold, or well-rotted manure, into the soil to improve its structure and fertility.
This will provide the nutrients necessary for healthy growth.
Here is the organic compost I recommend:
Drainage:
Ensure good drainage to prevent waterlogging, which can lead to root rot.
If your soil is heavy clay, consider raising the planting area or adding sand or gravel to improve drainage.
Planting Depth and Spacing
Proper planting depth and spacing are essential for tree ferns to establish and grow well:
Planting Depth:
Plant the fern at the same depth it was growing in its pot.
The crown, where the fronds emerge, should be just above the soil surface to prevent rot.
Spacing:
Allow sufficient space for the fern to grow and spread its fronds.
Depending on the species, space tree ferns at least 3 to 5 feet apart from other plants or structures to ensure adequate air circulation and light.
Watering
Consistent moisture is vital for tree ferns, especially during their establishment period:
Initial Watering:
After planting, water the tree fern thoroughly to settle the soil around the roots.
Regular Watering:
Keep the soil consistently moist but not waterlogged.
Water the trunk as well as the soil, as tree ferns absorb moisture through their trunks.
During dry periods, increase the frequency of watering.
This is a great way to use rainwater collected from a water butt.
Mulching
Mulching helps retain moisture, regulate soil temperature, and suppress weeds:
Mulch Layer:
Apply a thick layer of organic mulch, such as bark chips, leaf litter, or straw, around the base of the fern.
Ensure the mulch does not touch the trunk directly to avoid rot.
Here is the mulch I recommend using:
Protecting the Crown
The crown is the most critical part of the tree fern, where new fronds emerge:
Crown Care:
Avoid damaging the crown during planting and ensure it remains above the soil line.
Protection from Pests:
Keep an eye out for pests such as snails and slugs, which can damage new fronds.
Use organic pest control methods if necessary.
Staking
If you are planting a tall or top-heavy tree fern, staking may be necessary to provide support:
Stake Placement:
Place stakes around the fern without damaging the roots or trunk.
Tying the Fern:
Use soft ties to secure the fern to the stakes, allowing some movement for natural growth.
For more tips and inspiration for your shade garden, check out my guides:
New fronds emerging from my tree fern.
Caring for Tree Ferns
Here is how to make sure your tree ferns stays healthy:
Watering
Tree ferns require consistent moisture to thrive.
Here are some tips for proper watering:
Trunk Watering:
In addition to watering the soil, water the trunk of the tree fern.
The trunk can absorb moisture, which helps keep the plant hydrated.
Regular Watering:
Keep the soil consistently moist, especially during dry periods.
Tree ferns are susceptible to drying out, so ensure they receive regular water.
Avoid Waterlogging:
While tree ferns need consistent moisture, avoid waterlogging the soil.
Ensure good drainage to prevent root rot.
Feeding
Feeding your tree fern with the right nutrients will promote healthy growth:
Balanced Fertilizer:
Use a balanced, slow-release fertilizer during the growing season.
Avoid fertilizers high in nitrogen, as they can damage the plant.
Here is the fertilizer I recommend:
Frequency:
Feed the fern every 6-8 weeks during the growing season (spring and summer).
Reduce feeding in the fall and stop during winter when the plant is dormant.
Organic Options:
Consider using organic fertilizers like compost tea or fish emulsion, which provide nutrients without the risk of burning the plant.
Check out my guide: A Simple Recipe for Rich Compost Tea.
Mulching
Mulching helps retain soil moisture and provides additional nutrients as it decomposes:
Mulch Layer:
Apply a thick layer of organic mulch, such as bark chips, leaf litter, or straw, around the base of the fern.
Mulch helps regulate soil temperature and retain moisture.
Replenishing Mulch:
Check the mulch layer regularly and replenish it as needed to maintain its benefits.
Maintaining Humidity
Tree ferns thrive in humid environments, which can be a challenge in drier climates:
Misting:
Regularly mist the fronds with water to increase humidity around the plant.
Grouping Plants:
Grouping tree ferns with other plants can create a microclimate with higher humidity.
Using Humidifiers:
In indoor settings, use a humidifier to maintain the desired humidity levels.
Pruning Tree Ferns
Pruning is an essential part of maintaining the health and appearance of your tree fern.
Regular pruning helps encourage new growth, improves air circulation, and keeps the plant looking tidy.
Here is how to effectively prune a tree fern:
When to Prune
The best time to prune tree ferns is during the growing season, typically in spring and summer:
Growing Season:
Tree ferns are actively producing new fronds during this time, so pruning encourages fresh growth.
Avoid Dormant Periods:
Avoid pruning during the fall and winter when the plant is dormant, as this can stress the fern and hinder its recovery.
My tree fern right before I started pruning the old fronds.
New fronds emerging from the crown. A good sign that it is time to prune off the old brown fronds.
How to Prune
Follow these steps to prune your tree fern effectively:
Gather Tools:
Use sharp, clean pruning shears or a knife to ensure clean cuts and minimize damage.
Sterilize the tools before use to prevent the spread of diseases.
Identify Fronds to Remove:
Look for fronds that are yellowing, brown, damaged, or dead.
These fronds no longer contribute to the plant's health and should be removed.
Cut Close to the Trunk:
Make clean cuts as close to the trunk as possible without damaging the trunk itself.
This helps prevent disease and allows the plant to focus its energy on new growth.
Angle the Cut:
Cut at a slight angle to prevent water from sitting on the cut surface, which can lead to rot.
Remove Spent Fronds:
Remove fronds that have completed their lifecycle.
These are typically older fronds located lower on the trunk.
Tree fern after old fronds have been pruned.
Special Considerations
Crown Protection:
Be careful not to damage the crown, where new fronds emerge.
Avoid cutting too close to the crown, as this can harm the plant.
Young Plants:
For younger tree ferns, minimal pruning is needed.
Focus on removing only clearly dead or damaged fronds to avoid stressing the plant.
New fronds starting to extend and relax.
Winter Protection for Tree Ferns
Tree ferns, particularly those from tropical and subtropical regions, can be sensitive to cold weather.
Proper winter protection is essential to ensure they survive and thrive through the colder months.
Here’s how to effectively protect your tree ferns during winter:
Why Winter Protection is Important
Tree ferns are susceptible to frost and freezing temperatures, which can damage the fronds, trunk, and crown:
Frost Damage:
Frost can burn the delicate fronds, turning them brown and crispy.
Crown Protection:
The crown, where new fronds emerge, is particularly vulnerable and needs to be shielded from extreme cold.
Trunk Insulation:
The trunk, which stores moisture and nutrients, needs insulation to prevent freezing and cracking.
Insulating the Trunk
Insulating the trunk is a crucial step in protecting tree ferns during winter:
Wrap the Trunk:
Use horticultural fleece, burlap, or straw to wrap the trunk from the base to just below the crown.
This insulation helps keep the trunk warm and prevents frost damage.
Here is the insulation I recommend:
Secure the Wrapping:
Tie the wrapping material securely but not too tightly to allow some airflow and prevent moisture buildup, which can lead to rot.
Check Regularly:
Periodically check the wrapping to ensure it remains in place and adjust as necessary, especially after heavy winds or storms.
Protecting the Crown
The crown of the tree fern, where new fronds emerge, is the most critical area to protect:
Cover the Crown:
Use a thick layer of straw, horticultural fleece, or a frost protection blanket to cover the crown.
This layer acts as a barrier against frost and cold winds.
Allow Airflow:
Ensure the covering allows some airflow to prevent mold and mildew from developing.
Avoid using plastic, which can trap moisture.
Remove Covering in Spring:
Once the threat of frost has passed, remove the covering to allow the new fronds to emerge and grow without obstruction.
Additional Protection Tips
For areas with severe winters, consider additional protective measures:
Mini Greenhouses:
For smaller tree ferns or those in pots, consider using a mini greenhouse or cold frame to provide extra protection.
These structures can help maintain a warmer microclimate around the plant.
Mulching:
Apply a thick layer of mulch around the base of the tree fern to insulate the roots and soil.
Organic mulch like bark chips, straw, or leaf litter works well.
Watering During Winter:
Reduce watering during the winter months, but do not let the soil dry out completely.
Tree ferns still need some moisture, especially during dry, cold periods.
Move Potted Ferns Indoors:
If your tree ferns are in pots, move them to a sheltered location such as a greenhouse, conservatory, or even indoors.
Ensure they receive adequate light and humidity in their new location.
FAQs
Do tree ferns like sun or shade?
Tree ferns generally prefer shaded or partially shaded areas, which mimic their natural habitats under the canopy of larger trees in tropical and subtropical forests.
Too much direct sunlight can scorch their fronds, causing them to turn brown and dry out.
While some species can tolerate more light, providing them with dappled shade ensures they stay healthy and vibrant.
If you live in a hotter climate, consider planting tree ferns in an area that receives morning sun but is shaded during the hottest part of the day.
Alternatively, using shade cloth or positioning taller plants nearby can help create the ideal environment.
Where do tree ferns grow best?
Tree ferns grow best in environments that mimic their natural habitats, which are typically tropical or subtropical forests with high humidity, consistent moisture, and rich, well-drained soil.
They thrive in areas with mild temperatures and do not fare well in extreme cold or dry conditions.
Ideally, plant tree ferns in a location that provides protection from strong winds and extreme temperature fluctuations.
In terms of soil, they prefer a mix rich in organic matter.
Adding compost or well-rotted manure can improve soil quality, ensuring that the ferns receive the nutrients they need to grow.
Additionally, a location that provides some protection from the elements, such as under a tree canopy or along a shaded fence, can offer the best conditions for their growth.
Are tree ferns cold hardy?
Some tree fern species are more cold hardy than others.
For example, the Tasmanian tree fern (Dicksonia antarctica) is known for its greater tolerance to cold and can survive in temperatures as low as 20°F (-6°C) with proper protection.
However, most tree ferns are sensitive to frost and freezing temperatures.
If you live in a region with cold winters, it is crucial to provide winter protection by wrapping the trunk and covering the crown to prevent frost damage.
Moving potted tree ferns indoors or into a greenhouse during the winter can also help protect them from the cold.
It’s essential to know the specific cold tolerance of your tree fern species and take appropriate measures to ensure their survival during winter months.
Are tree ferns easy to care for?
Tree ferns are relatively easy to care for if you provide them with the right conditions.
They need consistent moisture, so regular watering is essential, particularly during dry periods.
The soil should be rich in organic matter and well-drained to prevent waterlogging.
Mulching around the base helps retain moisture and regulate soil temperature.
Tree ferns also benefit from regular feeding with a balanced, slow-release fertilizer during the growing season.
Pruning old or damaged fronds helps maintain their appearance and health.
While they do require some attention, the effort is well worth it for what they bring to a garden.
Is tree fern toxic to cats?
Tree ferns are not known to be toxic to cats, making them a safe addition to gardens and homes with pets.
However, it’s always best to monitor pets around any plant to prevent them from chewing on fronds or other parts.
While tree ferns themselves are not harmful, ingesting large quantities of any plant material can sometimes cause digestive upset in pets.
Ensuring that pets do not develop a habit of chewing on your plants will help keep both your plants and pets healthy.
If you notice any adverse reactions in your pets, consult a veterinarian promptly.
Is tree fern dead if the fronds turn brown?
Brown fronds can be a sign of several issues, such as too much sun, cold damage, or underwatering.
If the fronds turn brown, first check the watering routine to ensure the plant is receiving adequate moisture.
If underwatering isn’t the issue, consider whether the fern is getting too much direct sunlight or if it has been exposed to frost.
Despite brown fronds, the tree fern may still be alive.
Check the crown for firmness and the trunk for signs of life.
If the crown and trunk are still healthy, the fern can recover with proper care.
Prune away the brown fronds and adjust the fern’s environment to better suit its needs.
