Plan the perfect garden with our interactive tool →

How to Care for a Tree Fern

Tree fern (Dicksonia antarctica), native to Australia, is an attractive, dark green fern with a trunk that can grow as tall as 20 feet, and a canopy of fronds that can spread to more than 20 feet across. The tree fern grows happily in moist areas and filtered sunlight. With extra protection, mature tree ferns at least 4 years old can withstand temperatures as low as 15 degrees. Tree ferns can be planted outdoors, or grown in large, sturdy containers.

Plant the tree fern in filtered sunlight. Tree ferns planted in sun will survive, but will have stunted growth and shorter fronds.

Water the tree fern several times each week if it's shorter than 1 foot tall. Adequate water is especially important on hot, dry summer days. Water the fern slowly at ground level, and don't spray the fronds. Water at least once each week during the winter months.

Feed the fern once every spring, using a general purpose fertilizer applied according to the manufacturer's recommendations. Fertilizer is especially important for containerized tree ferns, but is optional for ferns grown in the ground.

Shelter the tree fern during the winter until it grows more than 2 feet tall. If the tree fern is in a container, bring it indoors. If the tree fern is grown outdoors, cover the plant on nights when a hard freeze is expected. Larger tree ferns can be protected by spreading dry straw in the crowns to prevent ice from forming. It can also be protected with an insulating blanket. After the tree fern reaches 4 feet, it will better withstand cold weather, but may still need some protection.

Care For A Diseased Australian Tree Fern

Plant Australian tree ferns in a partially shaded bed with well-draining, acidic soil and protection from strong winds to prevent damage from drought, excess moisture and poor nutrition. Water deeply but infrequently to prevent excess moisture in the soil. Watch for signs of improvement. Feed Australian tree ferns twice yearly in spring and midsummer to maintain the plant's health, which will lessen the likelihood of insect infestations. Apply full strength 10-10-10-10 ratio fertilizer to the soil around the base of the trunk and water deeply afterward to distribute the nutrients deep into the soil. Snip off the fronds at the base and discard them into a green-waste bin instead of using them for mulch or compost. Prevent and treat infestations of mites and mealybugs with a liberal application of horticultural oil.

Garden Guides