Fern trees (or tree ferns, as they are also called) are tropical plants that thrive in warm, humid conditions. The most common is the Australian fern tree (Sphaeropteris cooperi), which is a medium-sized tree that features long, feathery fronds. This plant is not a tree in the traditional sense, but really a giant fern that grows on one, thick stem, according to the University of Florida.
Fern trees are tropical plants and can only be grown outdoors year-round in United States Department of Agriculture (USDA) growing zones 10B through 11, according to the University of Florida. Freezing temperatures will quickly kill this plant, especially young trees.
Fern trees can reach a maximum height of 30 feet, with a thick trunk that can be as large as a foot in diameter. The trunk is reddish-brown and rather woolly in texture. The leaves, which are very lacy, average a little over a foot in length. The undersides of the leaves are covered with spores.
Soil and Water
This tree will grow in acidic, clay or sandy soils but prefers loamy soils rich in organic matter. Although the fern tree thrives in consistently moist soil, the soil should be well drained. Overly wet soil can lead to the development of fungal diseases.
Light and Culture
Australian fern trees thrive in shady areas, making them an excellent choice for planting near a shaded body of water or as an understory plant. Full shade or a bit of morning sunlight is best for this plant.
The Australian fern tree does not normally suffer from any serious diseases or insect problems, but it can be plagued by minor insect pests such as mealy bugs or mites. Home gardeners can leave the bugs alone or try to rid the tree of the bugs by spraying it with an insecticide. Termites may infest the trunk.