protecting your tree ferns

How to Protect Tree Ferns in Autumn and Winter: A Guide for Gardeners in Southern England

Tree ferns, with their exotic, prehistoric appearance, have become increasingly popular in gardens across the UK. In the southern parts of England, the milder climate allows for growing species like Dicksonia antarctica and Cyathea outdoors, but as autumn turns to winter, protecting these delicate plants becomes essential to ensure their survival through the colder months. Here’s a guide on how to protect tree ferns in autumn and winter, keeping your plants healthy and ready to thrive in the spring.

Focus on the Crown

The crown (the growing tip at the top of the trunk) is the most vulnerable part of a tree fern. If the crown is damaged, the plant may struggle to regenerate, even if the rest of the fern survives. To protect it:

• Pack the crown: Gently fill the top of the crown with straw or dry leaves to insulate it. This helps trap warmth around the vital growing point.
• Cover with fleece: Once the crown is packed, wrap horticultural fleece around the top of the fern. This helps protect it from wind and frost without smothering the plant.

Protecting the Trunk

Tree ferns store a lot of moisture in their trunks, which can be vulnerable to freezing. To prevent frost damage to the trunk:

• Wrap the trunk: Use horticultural fleece or bubble wrap to insulate the trunk. Start wrapping from the base upwards, ensuring there’s overlap between layers to keep the warmth in. Be careful not to wrap too tightly, as this can restrict airflow.
• Add a straw jacket: For additional insulation, you can pack straw between the fleece and the trunk. Straw is an excellent natural insulator and provides added warmth, particularly during harsh winters.
• Leave the base free: It’s important to keep the base of the tree fern clear. Tree ferns absorb moisture through the base, so leaving it exposed allows the plant to continue drawing water from the ground, even when the weather is cold.

Watering and Moisture Considerations

While tree ferns need protection from frost, they still require moisture through autumn and winter:

• Reduce watering in autumn: As the weather cools and growth slows, reduce the amount of water you give your ferns. Overwatering can lead to rot, especially if the plant is not actively growing.
• Ensure moisture retention: Keep the soil around your tree fern moist but not waterlogged. If the weather is dry, water the plant sparingly, ensuring that the trunk doesn’t dry out completely.
• Watch for frost: On particularly cold days, if temperatures are expected to drop significantly, you can lightly mist the fronds to increase humidity and prevent them from becoming brittle.

Dealing with Fronds: To Cut or Not to Cut?

Many gardeners wonder whether to cut back the fronds in autumn. The fronds of Dicksonia antarctica often turn brown over winter, but they still serve a protective function:

• Leave the fronds intact: It’s generally best to leave the fronds on the plant over winter, even if they look a bit ragged. They help shield the crown from frost and wind.
• Cutting in spring: In spring, once the risk of frost has passed, you can trim away the brown fronds to make way for fresh new growth. Leaving them on through winter acts as a natural defense against the elements.

Consider Additional Wind Protection

Tree ferns can be sensitive to cold winds, which can dry out and damage the fronds. In exposed areas, consider erecting a windbreak using garden screens or temporary barriers. You can also plant companion shrubs around your tree ferns to create a natural buffer against strong winds.

Winter in Containers: Additional Tips

If you’re growing tree ferns in containers, they’ll need a little extra care during winter:

• Move to a sheltered spot: If possible, relocate container-grown tree ferns to a sheltered area, such as against a south-facing wall, to reduce exposure to the cold.
• Insulate the container: Wrap bubble wrap or fleece around the container to insulate the roots. You can also lift the container off the ground using bricks or pot feet to prevent waterlogging.
• Bring them indoors: In particularly harsh winters, bringing your tree fern into an unheated greenhouse or shed can help them survive, especially in more northern or exposed areas.

Monitor the Weather

Keep an eye on weather forecasts, particularly during cold spells. If an extreme frost is predicted, consider adding extra layers of fleece or moving container plants to a more protected spot. It’s better to be cautious and add more protection than to risk losing a precious plant.

Unwrapping in Spring

Once the risk of frost has passed in spring, usually around late March to early April, you can begin to unwrap your tree fern. Remove the fleece and straw from the crown and trunk, allowing the plant to start growing again in the warmer weather. Check for new fronds, known as “croziers,” emerging from the crown, and provide regular water as growth resumes.

Tree ferns bring a tropical touch to gardens, but they do require extra care through the autumn and winter. By protecting the crown, insulating the trunk, and managing moisture levels, you can help your tree ferns thrive, even in colder conditions. With proper winter care, your tree ferns will emerge healthy and strong when spring arrives, ready to continue their dramatic, leafy display for another season.

With a little effort, your tree ferns can become long-term fixtures in your garden, surviving winter and flourishing year after year!

READ MORE