Many of the most popular plants are expected to bloom to add color and fragrance to the garden. Many others are grown to produce fruit or vegetables. Some are appreciated for their foliar color in autumn. Big trees are grown for shade. Turf grasses are grown as lawn. Evergreen shrubbery makes hedges. It seems that all plants perform particular tasks in the gardens which they inhabit.
Ferns only need to provide rich foliage. They do so very efficiently, with remarkably stylish and distinctive textures, and deep green color. Most ferns are evergreen, so only need to be groomed of their old foliage as it gets replaced by new foliage. Most of the few deciduous ferns are bare only briefly during their respective dormant seasons. Some can grow wild without any grooming at all.
Many ferns are famously tolerant of partial shade that is too dark for many other types of plants. Many are tolerant of confinement, so are happy in pots, planters and small atriums, or under stairs. Some ferns that are tolerant of both shade and confinement are popular as houseplants. Those that get too big or their situations are generally easy to dig and relocate, or divide into more plants.
There are only two species of tree fern that are common here; the Australian tree fern, and the New Zealand tree fern. Australian tree fern is taller with leaner trunks. Tasmanian tree fern is short and stout. These and more rare tree ferns are the only ferns that leave the ground as they develop ‘trunks’ of tightly bundled fibrous roots dispersed through the decayed remains of their rhizomes.
Their rhizomes are just their thick herbaceous stems. Those of tree ferns do not branch into more than a single terminal bud, so can not be divided. Rhizomes of most other ferns split into clumps of a few or many individual budded rhizomes, which can be divided if they get too crowded. Leaves that grow from the rhizomes are known as fronds. The fronds of almost all ferns are divided into smaller leaflets known as pinnae, which are suspended by leafstalks known as rachi.
This is one of those perennials that has mixed reviews. Although relatively tough once established, holly fern, Cyrtomium falcatum, is susceptible to rot and fungal leaf-spot. It likes to be watered somewhat regularly, but rots if the soil is constantly saturated. Leaf-spot is not as dangerous as it looks, but can be unsightly. Too much fertilizer (to correct the damage) can burn the foliage too.
It could be either an asset or a liability. With few exceptions, ferns do not want to be too exposed to direct sunlight or wind, especially during warm and dry weather. However, as long as they get just enough filtered light, they can be quite happy in sheltered spots that are a bit too shady for other plants. Most like to be watered regularly, and perhaps lightly fertilized in spring and summer.
Ferns tends to be . . . well, ‘ferny’, with divided or intricately lobed foliage. Staghorn ferns and bird’s-nest ferns are the more familiar of the rare exceptions. Staghorn ferns have two types of simple undivided fronds, and both types lack rachi. Bird’s-nest ferns have weirdly simple fronds that, although equipped with prominent rachi, lack any distinctive division or lobes that make ferns ‘ferny’.
The list of what ferns will not do is more noteworthy than the list of what they will do. They do not bloom with colorful or fragrant flowers. The do not produce fruit. Very few turn color in autumn, and their color is generally nothing to brag about. Most ferns will not maintain their appeal through drought, or if neglected too long. Nor will they tolerate heat and wind, especially in full sun exposure.
Staghorn ferns are epiphytes. They cling to tree trunks, rocks or whatever they happen to grab onto. They can root into decayed wood if it is porous enough, but they are satisfied to just cling to the exterior. They do not need soil. They sort of make their own soil by collecting debris that falls from the canopies of trees above. In the jungles where they live, they get all the water they need from rain. They often live in the crotches of branches because that is where they happen to land. (The epiphyte I wrote about earlier was just a palm that landed in the wrong place, but is not really an epiphyte. 
Tony Tomeo 