Tree fern

One of many kinds of tree fern, Dicksonia antarctica, soft tree fern, also called Hardy or Tasmanian, is native to southeastern Australia and Tasmania. Dicksonia is named for an 18th century British plants man, James Dickson. The species name “antarctica” refers to the southerly range of the plant. It is an ancient plant, dating back to the time of the dinosaurs. Of the six genera in the family Dicksoniaceae, it is the most tolerant of cold temperatures. It is a slow-growing evergreen, with a thick trunk. In the wild it can reach 20 to 30 feet high, but in gardens it is usually much smaller, to around 10 feet. The fronds form an impressive crown, hanging down as they mature. Individual fronds can grow 6- to 10-feet long. The pinnae, which make up each frond are dark green with a lighter underside. As some species are threatened in the wild, be sure to buy only nursery grown plants from reputable sources.

Tree Fern Growing Conditions

The plants like acidic soil with lots of organic matter and good drainage. Plant in a shaded or partially shaded location. It is also a good candidate for containers and greenhouses. This is the most cold tolerant tree fern, withstanding temperatures down to 20 F. It's hardy in zones 9 to 11.

Cultivation

During hot weather, water the trunk as well as the roots of the tree, as it is composed of aerial roots. Feed with a balance fertilizer in spring, or amend the soil around the tree with a layer of compost. In areas where below freezing temperatures occur, wrap in landscaping cloth or burlap padded with straw and protect new growth in the center of the crown by covering it with a pile of straw.

Tree ferns do not need pruning to shape, but cut off any yellowing fronds as they appear.

When a tree fern is stressed by high temperatures, drought or too much light, it is vulnerable to thrips, tiny insects that feed on the plant’s juices. Remove infected foliage and treat plant with insecticidal soap. Other non-chemical methods of control are attracting or introducing predators such as ladybugs, and planting repellant plants like garlic.

The plants are propagated by spores, or by removing offshoots from the base of mature plants. Fern do not have flowers. They reproduce by spores formed on the underside of the leaf or in special fronds. The sori which hold the spore bearing sporangia look like soft brown or black pads or scales in lines or stripes under the leafs. On Soft variety, the sori are tiny dots, in the edges of the pinnae, only 1 millimeter in diameter. Only some fronds, called fertile fronds, produce the reproductive structures.

Tree Fern Uses

A plant that can be an impressive focal point for a shade garden. Plant other ferns of various textures and colors beneath it for a cool, lush look.

In a large planter, it can give a patio a tropical feel when grouped with pots of bright colored dahlias and large leaved foliage plants such as elephant ears, Caladium and striped cannas. Epiphytic plants, some times called ‘air plants,’ are often found growing on the trunks in the wild. For a really exotic look, try growing some on your fern. Good choices include bromeliads like Tillandsia, and orchids such as Dendrobium or mosses and small ferns.

The center of the tree fern is a starchy vegetable that can be eaten or used as live stock fodder.

Related plants:

• Dicksonia punctilobula

Related articles:

• How to Plant a Tree