Calling an Australian tree fern a houseplant is a bit like calling a leopard a housecat—in their native habitats, these plants grow to 40 feet or more, easily too large for most indoor growing situations except for the largest of greenhouses. But they deserve inclusion because of their sheer beauty. These majestic ferns have curled fronds that emerge from the central leaf crown; individual fronds can reach four or five feet. A well-grown tree fern is a fast-growing plant, and will likely outgrow its space within a few years.
Light: Depends on heat and temperature, but they can handle full sun in temperate zones. They prefer partial shade however.
Water: Keep evenly moist all year, with very high humidity.
Temperature: They thrive between 65ºF and 80ºF.
Soil: Loose, well-drained potting mix.
Fertilizer: During growing season, feed with controlled-release fertilizer or biweekly with weak liquid fertilizer. Larger specimens are heavy feeders.
By spores. Propagation is typically left to growers.
Repot annually into larger pots with fresh, free-draining potting soil. When the plant reaches the maximum size allowed by the growing space, stop repotting to slow growth. Eventually, it will likely outgrow both the pot and the room.
The plant sold as an Australian tree fern is typically a C. cooperi. There are, however, about 1,000 different kinds of tree ferns, all found in tropical or subtropical settings. The New Zealand or Tasmanian tree fern is closely related, but is actually a Dicksonia antarctica. This plant tends to have a narrower crown than the Australian tree fern, but similar growth requirements.
Tree ferns thrive in mid-elevation tropical environments, where they can sometimes be found growing in great, prehistoric forests swathed in tepid mist. The key to growing a healthy tree fern is to provide ample humidity and consistency, avoiding extremes of heat, cold, and sunlight. Tree ferns don’t appreciate rapid changes in humidity or temperature, which will result in browning leaves. Beware of the tiny hairs on the trunks of Cyathea, as they can be irritating.