Australian Tree Fern
A Few Facts About The Australian Tree Fern
The Australian Tree Fern (Cyathea cooperi) is a large, showy fern which can make a wonderful addition the garden, whether placed in the ground or grown in a container. When properly cared for it can grow quite large, typically 30 to 40 feet tall, with branching leaves that can spread up to 15 feet (8 to 10 feet being typical). Its graceful arching leaves give the plant a definite tropical look, not surprising as it is in fact a tropical plant. It will do fine in temperate climates however, when it can be protected from extreme cold weather. The fern does tolerate some frosts but not always well. It does best in USDA Zones 8 through 11.
Plant Indoors, Or Better Yet Outdoors - Where the winter weather is too cold for the Australian Tree fern, it can be grown in a container for placement on a patio or simply kept indoors. It is a showy indoors plant to say the least, but be aware that the fronds are poisonous and handling the tree with bare hands can cause skin irritation. You'll want to think twice about having the plant indoors if you have small children or pets around. Outdoors, the fern can be a specimen plant in a nicely landscaped yard, and is particularly attractive when planted near a pond. It is even more attractive in the company of companion plants, which include Purple Fountain grass, the California Pepper tree, Ground Morning Glory, and the Ivory Tower Yucca. Once you have an established Australian Tree fern in place, you can probably find other good companion plants, or have none at all.
The Australian Tree fern grows from a single woody trunk which, for larger ferns, can approach a foot in diameter. The leaves are between a foot and 18 inches long, and are lacy in appearance. Spores on the undersides of the leaves are the plant's means of reproduction. Because the fern propagates from spores, propagation is usually best left to professionals, unless you are familiar with fern propagation techniques. The fern produces tiny, rather inconspicuous blooms, and seeds, but the seeds are sterile and cannot be used in propagating the plant.
Culture And Care - The fern is not particularly fussy as far as growing habits are concerned, though it must be kept moist, and does not like extremely hot weather or dry air. It can take a little extra attention when it comes to watering, as it is easy to over water as well as underwater the plant. In general, a good watering once a week will suffice; twice a week works best during very hot weather. Some owners say that their plant does best, once established, when watered by pouring water on the trunk. Also if the fern starts to suffer from leaves turning brown or dropping off, pouring a bucket of water over the crown can sometimes reverse the process. This may work well for a container plant, obviously more difficult for a 40 foot tall specimen. Plant the fern in sandy, loamy soil that is slightly acidic to acidic (pH in the range from 5.6 to 6.5). It does best when planted in a shady location, or in partial shade. In more northern latitudes you can plant it where it will get some direct sun, but shade is best. As the fern is a heavy feeder, you'll need to give it general purpose fertilizer periodically (once a month or once every 6 weeks).
Invasion Of The Tree Ferns - The Australian Tree fern is not usually considered to be an invasive plant. In its native habitat, the misty mountain sides of subtropical Australia and New Zealand, the fern grows in great numbers. When planted in a similar climate, the potential exists for it to become an invasive species. This is happening in Hawaii, where the plant is spreading and crowding our native plants. Since it propagates through spores, it can be difficult to control where the plant will grow when climatic conditions are just right, and in Hawaii that appears to be the case. In some locations there it is considered an invasive weed. In most of the continental United States this does not appear to be a problem.