Before considering what plants to grow, we need to look at the growing conditions. You need to ask yourself a few questions, like is the area shady all year or is the shade caused by a deciduous tree? If you answer when the tree is dormant, will there be access to winter sun for the north [southern hemishpere]. This significantly opens the range of plants that can be used. I personally find that if the shade from the tree is dappled or less during summer, then most plants will manage in this aspect, except of course those plants that demand full sun.
Is the shade caused by the wall of a building or shed? Is the area under eaves, hence minimal rainfall to the site and so extra irrigation will be required. I have never come upon a plant that will survive with no water and no light!
The soil in the area also needs to be examined. Free draining is essential to most plants but areas abutting buildings, especially on a slope may have impeded drainage caused by the building footings. Unless you want to grow bog plants that will tolerate wet periods following heavy rain, then the drainage will need to be resolved.
Dappled/filtered shade means that the canopy of trees allows some light through and the plants beneath are not in dense shade. Plants for this exposure, growing in well drained soil could include Aspidistra elatior or cast iron plant, Ruscus aculeatus growing to about 1 to 1.2 metres and Ruscus hypoglossum which is a smaller clumping form. Both of the Ruscus grow in dry shade. They can both fruit, but fruit is rarely formed, the theory being that you need a male and female plant – I have no idea how to determine this, so just accept the interesting foliage form.
Also for dappled shade are the Cordyline family. I grow in my rainforest garden Cordyline rubra, Cordyline petiolaris, Cordyline australis, Cordyline stricta and Cordyline obtecta. These plants are predominantly foliage plants as are the bulk of shade loving plants grown. But to me, this plant group is stunning for its sheer grace. When grown in these conditions i.e. out of full sun, they tend to be smaller. In full sun they are taller and robust plants and can burn on a hot day with low humidity.
Full shade is deep shade. Often formed from the space between 2 buildings that are close together with eaves overhanging. It is also usually very dry. This shade can also be formed by a mass of trees, often with large leaves, but these trees are often deciduous and so allow winter sunlight into the space when dormant. The Aspidistra and both the Ruscus will also grow here as they are very shade and drought tolerant plants. Surprisingly, the bulk of drought tolerant plants like those mentioned, need quite a lot of water to get them established; once to this point, they are remarkably tough.
Partial shade is when the space receives shade at some stage during the day. I find that this can be the most daunting area to plant if the sun exposure is during the hottest part of the day i.e. mid to late afternoon. These need to be pretty tough plants to tolerate shade for the better part of the day to then be blasted by 40 degree plus blasts of hot Australian sun. A plant that I have found will work in these conditions is Hedychium gardnerianum or the ginger lily. Some regard this plant as a nuisance when grown without regard for its expanding size, but when room is allowed for its expanding girth it is a wonderful plant. Good garden hygeine will remove any seed that may germinate; we have not experienced this occurrence to date.
There are quite a few Australian native grass-like perennials that grow well in various degrees of shade. I have found that they also look good with the plants mentioned above, because they are a variation on a theme – of growing foliage plants. Varieties that I have found do especially well are Dianella ‘Silverado’ with strappy grey foliage and silver variegation. Also Dianella caerulea ‘Goddess’ and Dianella tasmanica ‘Emerald Arch’ are good.
Plant labels often state full sun, but I have found that the bulk of dianellas prefer part to dappled shade. I grow in both. They may not flower as well, but I have a tendency to grow for foliage effect at the expense of flowers which are usually fleeting.
The Lomandra family of native perennials also has a species that I have found good in shade. This is Lomandra hystrix and its hybrids, Lomandra ‘Tropic Belle’ and Lomandra ‘Katie Belles’
They are bigger forms in general than the Lomandra longifolia varieties with a more graceful habit. But they do appear to prefer an acid soil to flourish.
Many of the Correa family grow and prefer some shade. Varieties like Correa ‘Marians’ Marvel’ and Correa ‘Mini Marian’ are excellent examples. The new Correa ‘Canberra Bells’ is also growing happily in my garden in dappled shade. The canopy here is high, but the area receives almost no direct sun. There is light without the sun.
Correa bauerlenii and Correa calycina are both very shade tolerant, tolerating more shade than the others. I have planted Correa calycina in my native garden at the base of a young Acacia melanoxylon, but last summer on a very hot day, the plant really struggled because it was receiving too much direct sun. In time, the canopy of the wattle will grow and protect it, and fortunately the blackwood wattle is a fast grower.
Both correas have green flowers, but birds seem to love these as much as the coloured forms. These green flowers in a native garden help to create that serenity that is so typical of the bush garden. The minimal use of loud colours is so endearing in the Australian bush. Restraint is definitely the essence here.