The key factors to successfully growing Australian plants in containers are exactly the same as for exotic plants – drainage and nutrition.
The main points to remember are that good drainage is even more important for certain natives (mainly those originating in arid areas with very light, sandy soils) and that plants in the Proteaceae* family require low phosphorus fertilisers.
When growing plants in containers it is important to know their type and origin so ask yourself the following questions:
• Tree, shrub or climber/groundcover?
• Does it originate in a high or low rainfall area?
• Is its natural habitat sun or shade?
• Natural soil type – light (sandy) or heavy (clay)?
The type of plant determines the ultimate pot size. Knowing its origins will tell you the type of growing medium you need, how much water and whether it should be placed in sun or shade. If the label doesn’t give you enough information, ask nursery staff.
Any type of container can be used, providing it has plenty of adequate sized drainage holes. Too small and they will drain too slowly and block up easily; too large and all your precious water will run away too fast. Most good quality terracotta and plastic pots come with good drainage holes; a medium-sized pot should have no less than four, about the size of a five-cent piece.
A good-quality, low-phosphorus potting mix, Searles Native Plant Mix, containing controlled-release fertiliser, is suitable for most Australian native plants.
Develop a watering regime which keeps the soil just moist but not too wet. Use your finger to test this. The frequency of watering is governed by:
• Time of year. Generally, less watering is required in winter. Unlike exotics, Queensland and northern NSW native plants are geared to a wet summer and dry winter. However, because these plants are still active in the cool season and, when potted, can’t draw any residual water from the soil, they will need some water to stop them drying out completely for too long.
• Sun or shade.
• Indoors or outdoors.
• Basket or pot – baskets require more frequent watering.
• Rate of growth – a fast-growing plant will take up more water.
• Use of water-saving granules.
The best time to water is in the evening or at night from late to early autumn, and in the tropics it’s best to water in the evening all year round.
Use a plant food such as Searles Native Plant Food at the recommended rate for the pot size and apply every 8-10 weeks from early spring through to autumn.
To conserve moisture, large pots of rainforest plants can be topped with organic mulch. Dryland species that usually grow in bare ground can be mulched with gravel or pebbles.
INDOOR AND OUTDOOR
Generally, rainforest and understorey plants can be grown indoors or on verandas and patios while those which require long hours of sun should be kept out of doors. However, even the most shadeloving plants need to be spelled out of doors occasionally, say at least one month twice a year, and sunlovers can be kept indoors for short periods (perhaps for a few days when flowering) or where there is direct sun for much of the day, for example a northfacing window. Air conditioning and artificial heating both cause plants to dry out; so ferns and rainforest species in particular will need to be ‘misted’ with a light spray of water to maintain healthy foliage.
SUNNY PATIO OR OUTDOORS
Alexandra and Piccabeen Palms
Norfolk Island pine
Baeckea, also known as Babingtonia
Ceratopetalum ‘Summer Star’
Little Penda (Xanthostemon verticillatus)
Callistemon ‘Little John’
Compact lilly pillys such as ‘Allyn Magic’ & ‘Cherry Surprise’
Banksia ‘Birthday Candles’
INDOORS & SHADE
Black Bean (Castanospermum australe)
Palms: e.g. Alexandra and Piccabeen palms (Archontophoenix alexandrae and A. cunninghamiana black palm (Normanbya normanbyi) fan palm (Licuala ramsayi) Carpentaria palm (Carpentaria acuminata) and walking stick palm (Linospadix monostachya)
Native ferns e.g. Blechnum, Davallia, Drynaria Zamia fern and Byfield fern
Various ficus species
Birds nest fern (Asplenium nitidium)
Sturt’s desert pea
Bracteantha (paper daisies)
Tassel fern (light shade)
Drynaria rigidula ‘whitei’ (fern)