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.